Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

PubMed Central

Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

2011-01-01

Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1205 - Calcium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1205 Calcium hydroxide. (a) Product. Calcium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

Effect of calcium hydroxide and triple antibiotic paste as intracanal medicaments on the incidence of inter-appointment flare-up in diabetic patients: An in vivo study.

PubMed

Pai, Swathi; Vivekananda Pai, A R; Thomas, Manuel S; Bhat, Vishal

2014-05-01

To evaluate and compare the effect of antibacterial intracanal medicaments on inter-appointment flare-up in diabetic patients. Fifty diabetic patients requiring root canal treatment were assigned into groups I, II, and III. In group I, no intracanal medicament was placed. In groups II and III, calcium hydroxide and triple antibiotic pastes were placed as intracanal medicaments, respectively. Patients were instructed to record their pain on days 1, 2, 3, 7, and 14. Inter-appointment flare-up was evaluated using verbal rating scale (VRS). Overall incidence of inter-appointment flare-up among diabetic patients was found to be 16%. In group I, 50% of the patients and in group II, 15% of the patients developed inter-appointment flare-up. However, no patients in group III developed inter-appointment flare-up. The comparison of these results was found to be statistically significant (P = 0.002; χ(2) = 12.426). However, with respect to intergroup comparison, only the difference between groups I and III was found to be statistically significant (P = 0.002; χ(2) = 12.00). Calcium hydroxide and triple antibiotic paste are effective for managing inter-appointment flare-ups in diabetic patients. Triple antibiotic paste is more effective than calcium hydroxide in preventing the occurrence of flare-up in diabetic patients.

Calcium hydroxide poisoning

MedlinePlus

These products contain calcium hydroxide: Cement Limewater Many industrial solvents and cleaners (hundreds to thousands of construction products, flooring strippers, brick cleaners, cement thickening products, and many ...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

21 CFR 872.3250 - Calcium hydroxide cavity liner.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Calcium hydroxide cavity liner. 872.3250 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3250 Calcium hydroxide cavity liner. (a) Identification. A calcium hydroxide cavity liner is a device material intended to be applied to the interior of a...

Effect of calcium hydroxide and triple antibiotic paste as intracanal medicaments on the incidence of inter-appointment flare-up in diabetic patients: An in vivo study

PubMed Central

Pai, Swathi; Vivekananda Pai, A. R.; Thomas, Manuel S.; Bhat, Vishal

2014-01-01

Aim: To evaluate and compare the effect of antibacterial intracanal medicaments on inter-appointment flare-up in diabetic patients. Materials and Methods: Fifty diabetic patients requiring root canal treatment were assigned into groups I, II, and III. In group I, no intracanal medicament was placed. In groups II and III, calcium hydroxide and triple antibiotic pastes were placed as intracanal medicaments, respectively. Patients were instructed to record their pain on days 1, 2, 3, 7, and 14. Inter-appointment flare-up was evaluated using verbal rating scale (VRS). Results: Overall incidence of inter-appointment flare-up among diabetic patients was found to be 16%. In group I, 50% of the patients and in group II, 15% of the patients developed inter-appointment flare-up. However, no patients in group III developed inter-appointment flare-up. The comparison of these results was found to be statistically significant (P = 0.002; χ2 = 12.426). However, with respect to intergroup comparison, only the difference between groups I and III was found to be statistically significant (P = 0.002; χ2 = 12.00). Conclusions: Calcium hydroxide and triple antibiotic paste are effective for managing inter-appointment flare-ups in diabetic patients. Triple antibiotic paste is more effective than calcium hydroxide in preventing the occurrence of flare-up in diabetic patients. PMID:24944440

Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

PubMed Central

Shalavi, S; Yazdizadeh, M

2012-01-01

The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5-12.8) and is classified chemically as a strong base. The lethal effects of calcium hydroxide on bacterial cells are probably due to protein denaturation and damage to DNA and cytoplasmic membranes. Calcium hydroxide has a wide range of antimicrobial activity against common endodontic pathogens but is less effective against Enterococcus faecalis and Candida albicans. Calcium hydroxide is also a valuable anti-endotoxin agent. However, its effect on microbial biofilms is controversial. PMID:23323217

Calcium hydroxide suppresses Porphyromonas endodontalis lipopolysaccharide-induced bone destruction.

PubMed

Guo, J; Yang, D; Okamura, H; Teramachi, J; Ochiai, K; Qiu, L; Haneji, T

2014-05-01

Porphyromonas endodontalis and its main virulence factor, lipopolysaccharide (LPS), are associated with the development of periapical diseases and alveolar bone loss. Calcium hydroxide is commonly used for endodontic therapy. However, the effects of calcium hydroxide on the virulence of P. endodontalis LPS and the mechanism of P. endodontalis LPS-induced bone destruction are not clear. Calcium hydroxide rescued the P. endodontalis LPS-suppressed viability of MC3T3-E1 cells and activity of nuclear factor-κB (NF-κB) in these cells, resulting in the reduced expression of interleukin-6 and tumor necrosis factor-α. In addition, calcium hydroxide inhibited P. endodontalis LPS-induced osteoclastogenesis by decreasing the activities of NF-κB, p38, and ERK1/2 and the expression of nuclear factor of activated T-cell cytoplasmic 1 in RAW264.7 cells. Calcium hydroxide also rescued the P. endodontalis LPS-induced osteoclastogenesis and bone destruction in mouse calvaria. Taken together, our present results indicate that calcium hydroxide suppressed bone destruction by attenuating the virulence of P. endodontalis LPS on bone cells.

Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients.

PubMed

Janssen, M J; van der Kuy, A; ter Wee, P M; van Boven, W P

1996-02-01

Prevention of secondary hyperparathyroidism in uremia necessitates correction of hyperphosphatemia and hypocalcemia. In order to avoid aluminum toxicity, calcium containing phosphate binders are used increasingly, instead of aluminium hydroxide. Recent studies have shown that calcium acetate has many characteristics of an ideal phosphate binder. It is, for instance, a more readily soluble salt compared with calcium carbonate. This advantage might, however, disappear if calcium carbonate is taken on an empty stomach, a few minutes before meals. We examined the efficacy of three different phosphate binding agents in a randomized prospective study of 53 patients on regular hemodialysis. Bicarbonate dialyses were performed with a dialysate calcium concentration of 1.75 mmol/l. After a three-week wash-out period, patients received either aluminum hydroxide (control group), calcium acetate, or calcium carbonate as their phosphate binder. Patients were instructed to take the calcium salts a few minutes before meals on an empty stomach, and aluminum hydroxide during meals. Serum calcium, phosphate, intact parathormone, and alkaline phosphatase levels were determined every month. Patient compliance was estimated every month by asking the patients which phosphate binder and what daily dose they had used. Aluminum hydroxide tended to be the most effective phosphate binder. The mean +/- SEM required daily dose of calcium acetate at 12 months was 5.04 +/- 0.60 g, corresponding to 10.1 +/- 1.20 tablets of 500 mg. Co-medication with aluminum hydroxide, however, was needed (1.29 +/- 0.54 g per day, corresponding to 2.6 +/- 1.08 tablets of 500 mg). The required daily calcium carbonate dose appeared to be 2.71 +/- 0.48 g, corresponding to 5.4 +/- 0.95 capsules of 500 mg, with an adjuvant daily aluminum hydroxide dose of 0.69 +/- 0.27 g, corresponding to 1.4 +/- 0.55 tablets of 500 mg (p = 0.0055). Thus, the mean daily doses of elemental calcium were comparable between the calcium

Conversion coatings prepared or treated with calcium hydroxide solutions

NASA Technical Reports Server (NTRS)

Maxey, Jason (Inventor); Nelson, Carl (Inventor); Eylem, Cahit (Inventor); Minevski, Zoran (Inventor); Clarke, Eric (Inventor)

2002-01-01

A conversion coating process that forms a stable and corrosion-resistant oxide layer on metal or metal oxide substrates or layers. Particularly, the conversion coating process involves contacting the metal or metal oxide substrate or layer with the aqueous calcium hydroxide solutions in order to convert the surface of the substrate to a stable metal oxide layer or coating. According to the present invention, the calcium hydroxide solution is prepared by removing carbon dioxide from water or an aqueous solution before introducing the calcium hydroxide. In this manner, formation of calcium carbonate particles is avoided and the porosity of the conversion coating produced by the calcium hydroxide solution is reduced to below about 1%.

Antimicrobial activity of calcium hydroxide and chlorhexidine on intratubular Candida albicans

PubMed Central

Jacques Rezende Delgado, Ronan; Helena Gasparoto, Thaís; Renata Sipert, Carla; Ramos Pinheiro, Claudia; Gomes de Moraes, Ivaldo; Brandão Garcia, Roberto; Antônio Hungaro Duarte, Marco; Monteiro Bramante, Clóvis; Aparecido Torres, Sérgio; Pompermaier Garlet, Gustavo; Paula Campanelli, Ana; Bernardineli, Norberti

2013-01-01

This study investigated the efficacy of calcium hydroxide and chlorhexidine gel for the elimination of intratubular Candida albicans (C. albicans). Human single-rooted teeth contaminated with C. albicans were treated with calcium hydroxide, 2% chlorhexidine gel, calcium hydroxide plus 2% chlorhexidine gel, or saline (0.9% sodium chloride) as a positive control. The samples obtained at depths of 0–100 and 100–200 µm from the root canal system were analyzed for C. albicans load by counting the number of colony forming units and for the percentage of viable C. albicans using fluorescence microscopy. First, the antimicrobial activity of calcium hydroxide and the 2% chlorhexidine gel was evaluated by counting the number of colony forming units. After 14 days of intracanal medication, there was a significant decrease in the number of C. albicans colony forming units at a depth of 0–100 µm with chlorhexidine treatment either with or without calcium hydroxide compared with the calcium hydroxide only treatment. However, there were no differences in the number of colony forming units at the 100–200 µm depth for any of the medications investigated. C. albicans viability was also evaluated by vital staining techniques and fluorescence microscopy analysis. Antifungal activity against C. albicans significantly increased at both depths in the chlorhexidine groups with and without calcium hydroxide compared with the groups treated with calcium hydroxide only. Treatments with only chlorhexidine or chlorhexidine in combination with calcium hydroxide were effective for elimination of C. albicans. PMID:23538639

Antibiofilm efficacy of silver nanoparticles as a vehicle for calcium hydroxide medicament against Enterococcus faecalis.

PubMed

Afkhami, Farzaneh; Pourhashemi, Seyyed Jalal; Sadegh, Mona; Salehi, Yasaman; Fard, Mohammad Javad Kharrazi

2015-12-01

The aim of the present study was to investigate antibacterial characteristic and Enterococcus faecalis (E. faecalis) biofilm suppression effect of different vehicles of calcium hydroxide as intracanal medicaments in short and long-term. Fifty-four human single-root teeth were contaminated with E. faecalis bacteria. The teeth were randomly divided into three experimental (n=16) and one control group (n=6). Each group was then exposed to various intracanal medicaments, namely calcium hydroxide paste (group 1), calcium hydroxide with chlorhexidine (group 2), calcium hydroxide with silver nanoparticles suspension (AgNPs) (group 3), and saline as the control group (group 4). Cultures were made from each group after one week and one month, and the number of colonies was counted. Moreover, a sample of each group was examined under electron microscope. Kruskal-Wallis test served for inter-group comparisons, and Mann-Whitney test served for comparison between the two incubation periods. All the intracanal medicaments resulted in significant decrease in number of colonies compared to control group in both incubation periods. After one week, the mixture of calcium hydroxide and AgNPs was the most effective medicament against E. faecalis bacteria (p<.05). No significant difference in antibacterial effect of the medicaments existed after one month incubation period (p>.05). AgNPs was more effective on the E. faecalis biofilm than other tested vehicles in short-term medication. AgNPs seems to have a good potential to be used as an appropriate vehicle of calcium hydroxide in order to eliminate of E. faecalis biofilm from human dentine in short-term. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

40 CFR 415.310 - Applicability; description of the calcium hydroxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... calcium hydroxide production subcategory. 415.310 Section 415.310 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Hydroxide Production Subcategory § 415.310 Applicability; description of the calcium hydroxide production subcategory. The provisions of this subpart are applicable to discharges...

Nonsurgical Clinical Management of Periapical Lesions Using Calcium Hydroxide-Iodoform-Silicon-Oil Paste

PubMed Central

Al Khasawnah, Qusai; Hassan, Fathi; Malhan, Deeksha; Engelhardt, Markus; Daghma, Diaa Eldin S.; Obidat, Dima; Lips, Katrin S.; Heiss, Christian

2018-01-01

Background The study aim is to avoid tooth extraction by nonsurgical treatment of periapical lesion. It assesses healing progress in response to calcium hydroxide-iodoform-silicon oil paste (CHISP). Numeric Pain Rating Scale was used to validate the approach. Furthermore, CHISP was used to treat cystic lesions secondary to posttraumatic avulsion of permanent teeth. Materials and Methods Over 200 patients with radicular cysts were treated with CHISP through the root canal. Radiographs were used to verify lesion size and position, ensure correct delivery to the site, and monitor the progress of bone healing in the lesion area. Ten males and 10 females were randomly selected for statistical assessment. Results No severe pain, complications, or failure in cyst healing was reported. Complete healing was achieved in an average of 75 days. Furthermore, healing of radicular cyst secondary to posttraumatic tooth avulsion was successful. Conclusion CHISP indicated an antiseptic effect, which enhanced and shortened healing time of periapical lesions. The less invasive procedure avoids tooth extraction and reduces bone resorption. Cyst management with CHISP can remedy failed root canal treatments. The results show a bone regenerative capacity of CHISP suggested in first rapid phase and a second slow phase. PMID:29619378

Predictive Mechanical Characterization of Macro-Molecular Material Chemistry Structures of Cement Paste at Nano Scale - Two-phase Macro-Molecular Structures of Calcium Silicate Hydrate, Tri-Calcium Silicate, Di-Calcium Silicate and Calcium Hydroxide

NASA Astrophysics Data System (ADS)

Padilla Espinosa, Ingrid Marcela

Concrete is a hierarchical composite material with a random structure over a wide range of length scales. At submicron length scale the main component of concrete is cement paste, formed by the reaction of Portland cement clinkers and water. Cement paste acts as a binding matrix for the other components and is responsible for the strength of concrete. Cement paste microstructure contains voids, hydrated and unhydrated cement phases. The main crystalline phases of unhydrated cement are tri-calcium silicate (C3S) and di-calcium silicate (C2S), and of hydrated cement are calcium silicate hydrate (CSH) and calcium hydroxide (CH). Although efforts have been made to comprehend the chemical and physical nature of cement paste, studies at molecular level have primarily been focused on individual components. Present research focuses on the development of a method to model, at molecular level, and analysis of the two-phase combination of hydrated and unhydrated phases of cement paste as macromolecular systems. Computational molecular modeling could help in understanding the influence of the phase interactions on the material properties, and mechanical performance of cement paste. Present work also strives to create a framework for molecular level models suitable for potential better comparisons with low length scale experimental methods, in which the sizes of the samples involve the mixture of different hydrated and unhydrated crystalline phases of cement paste. Two approaches based on two-phase cement paste macromolecular structures, one involving admixed molecular phases, and the second involving cluster of two molecular phases are investigated. The mechanical properties of two-phase macromolecular systems of cement paste consisting of key hydrated phase CSH and unhydrated phases C3S or C2S, as well as CSH with the second hydrated phase CH were calculated. It was found that these cement paste two-phase macromolecular systems predicted an isotropic material behavior. Also

Comparative evaluation of different forms of calcium hydroxide in apexification.

PubMed

Ghosh, Subhankar; Mazumdar, Dibyendu; Ray, Pradip Kumar; Bhattacharya, Bhaswar

2014-01-01

One out of every two children sustains a dental injury most often between 8 and 10 years of age. Majority of these teeth subsequently become non-vital and most often with immature apex. Management of these teeth is an enormous challenge for lack of apical stop. Calcium hydroxide in various formulations has maximum literature support in favor of successful apexification or induced apical closure. The aim of the following study is to determine the efficacy of calcium hydroxide in a different formulation to induce apexification. The present study was undertaken on 51 children of 8-10 years of age (both sexes) at Dr. R Ahmed Dental College and Hospital from April 2006 to March 2007. All children had one or two maxillary permanent central incisor (s), non-vital and apices open. In all the cases, apexification was attempted with either calcium hydroxide mixed with sterile distilled water, or calcium hydroxide plus iodoform in methyl cellulose base, or calcium hydroxide plus iodoform in polysilicone oil base. The success of apexification was determined on the basis of clinical and radiographic criteria. In the pre-operative asymptomatic cases (72.55%), failure occurred in only 5.45% cases and pre-operative symptomatic cases failure rate was as high as 35.71%. Success rate was 94.6% in cases with narrow open apices, whereas 64.28% in wide open apices. In cases with pre-existing apical radiolucencies, successful apexification occurred in 63.63% and success rate was 92.5% in the cases without pre-existing apical radiolucencies. Average time consumed for apexification was minimum with calcium hydroxide plus iodoform in polysilicone oil base. The overall success rate observed to be 86.27%, which is in close proximity to the findings of most of the previous studies across the globe.

Influence of calcium hydroxide debris on the quality of endodontic apical seal.

PubMed

Contardo, L; De Luca, M; Bevilacqua, L; Breschi, L; Di Lenarda, R

2007-10-01

The aim of the study was to study investigate the influence of calcium hydroxide used as intermediate medication on the quality of apical seal of a silicon based and an experimental resin based endodontic sealer. Eighty endodontic canals were prepared and divided in four groups. Calcium hydroxide was applied in groups 2 and 4. After 7 days, medication was removed and canals were filled with gutta-percha and RoekoSeal Automix (groups 1 and 2) or Scotchbond MP+C&B cement B (groups 3 and 4). Specimens were placed into India ink, cleared and analyzed under a stereomicroscope to investigate apical leakage. Specimens that received calcium hydroxide medication showed leakage means higher than the corresponding untreated ones (i.e. group 1< group 2 and group 3< group 4; P<0.001). Calcium hydroxide interferes with the sealing ability of silicon based sealer, since it frequently remains entrapped within the endodontic space even after careful removal procedures.

Apical closure of mature molar roots with the use of calcium hydroxide.

PubMed

Rotstein, I; Friedman, S; Katz, J

1990-11-01

Calcium hydroxide may induce apical root closure in affected mature teeth as well as in immature teeth. Once an apical hard tissue barrier is formed, a permanent root canal filling can be safely condensed. Two cases are described in which calcium hydroxide induced apical root closure in mature molar teeth where the apical constriction was lost because of chronic inflammatory process.

Study on Kinetic Mechanism of Bastnaesite Concentrates Decomposition Using Calcium Hydroxide

NASA Astrophysics Data System (ADS)

Cen, Peng; Wu, Wenyuan; Bian, Xue

2018-06-01

The thermal decomposition of bastnaesite concentrates using calcium hydroxide was studied. Calcium hydroxide can effectively inhibit the emission of fluorine during roasting by transforming it to calcium fluoride. The decomposition rate increased with increasing reaction temperature and amount of calcium hydroxide. The decomposition kinetics were investigated. The decomposition reaction was determined to be a heterogeneous gas-solid reaction, and it followed an unreacted shrinking core model. By means of the integrated rate equation method, the reaction was proven to be kinetically first order. Different reaction models were fit to the experimental data to determine the reaction control process. The chemical reaction at the phase interface controlled the reaction rate in the temperatures ranging from 673 K to 773 K (400 °C to 500 °C) with an apparent activation energy of 82.044 kJ·mol-1. From 773 K to 973 K (500 °C to 700 °C), diffusion through the solid product's layer became the determining step, with a lower activation energy of 15.841 kJ·mol-1.

Influence of calcium hydroxide on the post-treatment pain in Endodontics: A systematic review

PubMed Central

Anjaneyulu, K.; Nivedhitha, Malli Sureshbabu

2014-01-01

Introduction: Pain of endodontic origin has been a major concern to the patients and the clinicians for many years. Post-operative pain is associated with inflammation in the periradicular tissues caused by irritants egressing from root canal during treatment. It has been suggested that calcium hydroxide intra-canal medicament has pain-preventive properties because of its anti-microbial or tissue altering effects. Some dispute this and reasoned that calcium hydroxide may initiate or increase pain by inducing or increasing inflammation. Objective: To evaluate the effectiveness of calcium hydroxide in reducing the post-treatment pain when used as an intra-canal medicament Materials and Methods: The following databases were searched: PubMed CENTRAL (until July 2013), MEDLINE, and Cochrane Database of Systematic Reviews. Bibliographies of clinical studies and reviews identified in the electronic search were analyzed for studies published outside the electronically searched journals. The primary outcome measure was to evaluate the post-treatment pain reduction when calcium hydroxide is used as an intra-canal medicament in patients undergoing root canal therapy. Results: The reviews found some clinical evidence that calcium hydroxide is not very effective in reducing post-treatment pain when it is used alone, but its effectiveness can be increased when used in combination with other medicaments like chlorhexidine and camphorated monochlorophenol (CMCP). Conclusion: Even though calcium hydroxide is one of the most widely used intra-canal medicament due to its anti-microbial properties, there is no clear evidence of its effect on the post-treatment pain after the chemo-mechanical root canal preparation. PMID:24944439

LIGNOSULFONATE-MODIFIED CALCIUM HYDROXIDE FOR SULFUR DIOXIDE CONTROL

EPA Science Inventory

The article discusses the use of lignosulfonate-modified calcium hydroxide Ca(OH)2 for sulfur dioxide (SO2) control. The limestone injection multistage burner (LIMB) process is currently being developed at the U.S. EPA as a low cost retrofittable technology for controlling oxides...

75 FR 28608 - Calcium Hydroxide; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2010-0411; FRL-8826-7] Calcium Hydroxide; Receipt of... Department of Agriculture to use the pesticide calcium hydroxide (CAS No. 1305-62-0) to treat up to 1,000...: [email protected] . SUPPLEMENTARY INFORMATION: I. General Information A. Does this Action Apply to Me...

40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

40 CFR 721.10018 - Calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Calcium hydroxide oxide silicate (Ca6... New Uses for Specific Chemical Substances § 721.10018 Calcium hydroxide oxide silicate (Ca6(OH)2O2... substance identified as calcium hydroxide oxide silicate (Ca6(OH)2O2(Si2O5)3) (PMN P-01-442; CAS No. 13169...

Microstructure of amorphous aluminum hydroxide in belite-calcium sulfoaluminate cement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Fei; Yu, Zhenglei; Yang, Fengling

Belite-calcium sulfoaluminate (BCSA) cement is a promising low-CO{sub 2} alternative to ordinary Portland cement. Herein, aluminum hydroxide (AH{sub 3}), the main amorphous hydration product of BCSA cement, was investigated in detail. The microstructure of AH{sub 3} with various quantities of gypsum was investigated via scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The AH{sub 3} with various morphologies were observed and confirmed in the resulting pastes. Particular attention was paid to the fact that AH{sub 3} always contained a small amount of Ca according to the results of EDS analysis. The AH{sub 3} was then characterized via highmore » resolution transmission electron microscopy (HRTEM). The results of HRTEM indicated that Ca arose from nanosized tricalcium aluminate hexahydrate which existed in the AH{sub 3}.« less

Fabrication of porous low crystalline calcite block by carbonation of calcium hydroxide compact.

PubMed

Matsuya, Shigeki; Lin, Xin; Udoh, Koh-ichi; Nakagawa, Masaharu; Shimogoryo, Ryoji; Terada, Yoshihiro; Ishikawa, Kunio

2007-07-01

Calcium carbonate (CaCO(3)) has been widely used as a bone substitute material because of its excellent tissue response and good resorbability. In this experimental study, we propose a new method obtaining porous CaCO(3) monolith for an artificial bone substitute. In the method, calcium hydroxide compacts were exposed to carbon dioxide saturated with water vapor at room temperature. Carbonation completed within 3 days and calcite was the only product. The mechanical strength of CaCO(3) monolith increased with carbonation period and molding pressure. Development of mechanical strength proceeded through two steps; the first rapid increase by bonding with calcite layer formed at the surface of calcium hydroxide particles and the latter increase by the full conversion of calcium hydroxide to calcite. The latter process was thought to be controlled by the diffusion of CO(2) through micropores in the surface calcite layer. Porosity of calcite blocks thus prepared had 36.8-48.1% depending on molding pressure between 1 MPa and 5 MPa. We concluded that the present method may be useful for the preparation of bone substitutes or the preparation of source material for bone substitutes since this method succeeded in fabricating a low-crystalline, and thus a highly reactive, porous calcite block.

Flare-ups incidence and severity after using calcium hydroxide as intracanal dressing.

PubMed

Ghoddusi, Jamileh; Javidi, Maryam; Zarrabi, Mohammad Hasan; Bagheri, Hossein

2006-01-01

Acute pain and swelling following endodontic treatment are a challenge for both the patient and the dentist. According to previous studies, the incidence of flare-ups increases after endodontic treatment of teeth with necrotic pulps. Calcium hydroxide is currently used as a multi-purpose drug in root canal therapy. The aim of this study was to evaluate the incidence and severity of flare-ups after treatment of pulpless teeth using calcium hydroxide as an intracanal dressing. Sixty patients with single-root necrotic teeth participated in this study. These patients were randomly divided into three groups of 20. The patients were treated in Group A in a single-visit approach, in group B with a two-visit approach without any intracanal dressing and group C with a two-visit approach using calcium hydroxide as an intracanal dressing for one week. All of the patients were followed for 72 hours after each treatment session. The information about the incidence and severity of pain and swelling was recorded in tables, using a modified Visual Analogue Scale for pain severity measurement and a scale with four degrees for measuring the severity of swelling. The data were analyzed by chi-square test and GENMODE procedure.

Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

PubMed

Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

2017-11-01

Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH) 2 ) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH) 2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH) 2 -glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl 2 ) at room temperature, but that in Ca(OH) 2 -water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH) 2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calcium leaching behavior of cementitious materials in hydrochloric acid solution.

PubMed

Yang, Huashan; Che, Yujun; Leng, Faguang

2018-06-11

The calcium leaching behavior of cement paste and silica fume modified calcium hydroxide paste, exposed to hydrochloric acid solution, is reported in this paper. The kinetic of degradation was assessed by the changes of pH of hydrochloric acid solution with time. The changes of compressive strength of specimens in hydrochloric acid with time were tested. Hydration products of leached specimens were also analyzed by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG), and atomic force microscope (AFM). Tests results show that there is a dynamic equilibrium in the supply and consumption of calcium hydroxide in hydrochloric acid solution, which govern the stability of hydration products such as calcium silicate hydrate (C-S-H). The decrease of compressive strength indicates that C-S-H are decomposed due to the lower concentration of calcium hydroxide in the pore solution than the equilibrium concentration of the hydration products. Furthermore, the hydration of unhydrated clinker delayed the decomposition of C-S-H in hydrochloric acid solution due to the increase of calcium hydroxide in pore solution of cementitious materials.

ELIMINATION OF INTRACANAL INFECTION IN DOGS' TEETH WITH INDUCED PERIAPICAL LESIONS AFTER ROTARY INSTRUMENTATION: INFLUENCE OF DIFFERENT CALCIUM HYDROXIDE PASTES

PubMed Central

Soares, Janir Alves; Leonardo, Mário Roberto; da Silva, Léa Assed Bezerra; Tanomaru, Mário; Ito, Izabel Yoko

2006-01-01

The aim of this study was to evaluate the antiseptic efficacy of rotary instrumentation associated with calcium hydroxide-based pastes prepared with different vehicles and antiseptics. Chronic periapical lesions were experimentally induced in 72 premolar root canals of four dogs. Under controlled asepsis, after initial microbiological sampling (A1), the root canals were instrumented using the ProFile system in conjunction with 5.25% sodium hypochlorite and the intracanal medication was placed. Four experimental groups were formed according to the pastes used: group 1- Calen (n=18), group 2- Calen+CPMC (n=20), group 3- Ca(OH)2 p.a.+ anaesthetic solution (n=16) and group 4- Ca(OH)2 p.a.+ 2% chlorhexidine digluconate (n=18). After 21 days, the pastes were removed; the canals were emptied and 96 hours later a second microbiological sample was obtained (A2). The incidence of positive microbiological cultures and the number of cfus in stages A1 and A2 were compared statistically by the Wilcoxon test while the influence of the different treatments in intracanal infection was evaluated by Kruskal-Wallis test at 5% significance level (p<0.05). Large numbers of strict and facultative anaerobes, and viridans group streptococci were found in 100% of root canals of A1 samples. Among A2 samples, all treatments showed significant reduction of cfus and positive cultures (p<0.05), but only groups 3 and 4 showed 100% of root canals free of microorganisms. Rotary instrumentation plus NaOCl 5.25% associated with intracanal medication produced a drastic reduction or elimination of intracanal microbiota, whose performance was not influenced by the nature of the vehicle or the antiseptic added to the Ca(OH)2 p.a. PMID:19089068

A comparison between effect of photodynamic therapy by LED and calcium hydroxide therapy for root canal disinfection against Enterococcus faecalis: A randomized controlled trial.

PubMed

Asnaashari, Mohammad; Ashraf, Hengameh; Rahmati, Afsaneh; Amini, Neda

2017-03-01

Insufficient root canal disinfection is one of the main reasons for persistent periapical pathology. Photodynamic therapy (PDT) has been proven effective in disinfecting infected root canals. The aim of this study was to evaluate the antimicrobial effect of photo activated disinfection (PAD) when using toluidine blue as photosensitizer and a LED lamp after the conventional treatment, and comparing it with calcium hydroxide therapy in vivo. This clinical trial includes 20 patients with molars requiring endodontic retreatment. After the conventional treatment, first microbiological samples were obtained using sterile rotary ProTaper F2 file and 3 paper points and transferred to a microbiology laboratory. Group 1 (n=10) specimens underwent PAD with photosensitizer (PS) solution (0.1mg/mL TB) and irradiation with Fotosan light emitting diode (LED) lamp (635nm, 200mW/cm2) for 60s. Creamy Ca(OH)2 paste was used in group 2 (n=10) for two weeks. A second sample was then obtained. The samples were cultured and then bacterial colonies were counted. Data included number of colony forming units (CFUs) before and after treatments, analyzed by t-test and analysis of covariance (ANCOVA) using SPSS vs.18. A significant difference between results of before and after treatment of both groups (calcium hydroxide therapy p=0.02<0.05, PAD p<0.0001) indicated the efficacy of both treatments. The mean numbers for log 10CFUs/mL before calcium hydroxide therapy and PAD with LED irradiation was 10.1968 and 11.3773. After treatment, the mean numbers were 9.4202 and 8.3772, respectively. The difference in results after treatment between groups was significant (p=0.01<0.05) and indicate that PAD was more effective. PAD and calcium hydroxide therapy, as auxiliary methods adjunct to conventional root canal therapy, are both effective in root canal disinfection. In comparison with calcium hydroxide therapy, PAD leads to a greater reduction in enterococcus faecalis number in the infected root

Effect of Calcium Hydroxide, Chlorhexidine Digluconate and Camphorated Monochlorophenol on the Sealing Ability of Biodentine Apical Plug.

PubMed

Srivastava, Aastha Arora; Srivastava, Harshit; Prasad, Ashwini B; Raisingani, Deepak; Soni, Dileep

2016-06-01

Teeth with immature apex are managed by establishing an apical plug using various materials and techniques. However, the use of previously placed intracanal medicament may affect the sealing ability of permanent filling material used as an apical plug. To evaluate the effect of removal of previously placed Calcium Hydroxide, Chlorhexidine Digluconate and Camphorated Monochlorophenol as an intracanal medicament on the sealing ability of the Biodentine as an apical plug. A total of 72 recently extracted human permanent teeth with single root were selected and stored in saline at room temperature. The crown portion of each tooth was removed at the level of cemento enamel junction; 14mm root length was taken as standard length. All the roots were submerged in 20% sulphuric acid up to 3 mm from the apex, for four days for root resorption. One sample was cut longitudinally to look for root resorption under stereo microscope. The canal preparation was done; the roots were kept in moist gauze after instrumentation. A total of 71 roots were randomly divided into three groups. GROUP 1:Calcium hydroxide paste, GROUP 2: Chlorhexidine digluconate, GROUP 3: Camphorated Monochlorophenol (CMCP). The medicaments were removed with stainless steel hand files and 0.5% sodium hypochlorite irrigation. After removal of medicament Biodentine was placed in apical third of resorbed roots and the remaining portion of the canals was filled with gutta-percha. All the 71 roots were analysed with fluid filtration method for evaluating microleakage. Comparing all the three groups statistically there was no significant difference. The mean values were found more for group 1 followed by group 2 & 3. All the groups showed microleakage. Calcium hydroxide showed the maximum microleakage followed by Chlorhexidine digluconate and least with CMCP.

A role for calcium hydroxide and dolomite in water: acceleration of the reaction under ultraviolet light.

PubMed

Nagase, Hiroyasu; Tsujino, Hidekazu; Kurihara, Daisuke; Saito, Hiroshi; Kawase, Masaya

2014-04-01

Organic environmental pollutants are now being detected with remarkably high frequency in the aquatic environment. Photodegradation by ultraviolet light is sometimes used as a method for removing organic chemicals from water; however, this method is relatively inefficient because of the low degradation rates involved, and more efficient methods are under development. Here we show that the removal of various organic pollutants can be assisted by calcined dolomite in aqueous solution under irradiation with ultraviolet light. It was possible to achieve substantial removal of bisphenol A, chlorophenols, alkylphenols, 1-naphthol and 17β-estradiol. The major component of dolomite responsible for the removal was calcium hydroxide. Our results demonstrate that the use of calcium hydroxide with ultraviolet light irradiation can be a very effective method of rapidly removing organic environmental pollutants from water. This is a new role for calcium hydroxide and dolomite in water treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparative evaluation of effectiveness of sodium dichloroisocyanurate and calcium hydroxide against Candida albicans.

PubMed

Kurian, Jacob; Bolla, Nagesh; Damaraju, Bhargavi

2012-09-01

Candida albicans is the most commonly isolated fungi from the oral cavity. It is the most infective to various intracanal medicaments and is considered as invasive yeast. Sodium dichloroisocyanurate (NaDCC) which is used as a disinfectant and as a biocide in treating potable water has similar action to that of sodium hypochlorite against microbes. The aim of the present study is to compare the effectiveness of calcium hydroxide and NaDCC against Candida albicans. After obtaining the stock cultures of Candida, the isolates were divided into six groups which were exposed to different concentrations of NaDCC and calcium hydroxide Ca(OH)₂. Group 1 consisted of the isolates which were subdivided into three groups, subjected to three different concentrations of NaDCC. Group 2 also consisted of three subgroups exposed to three different concentrations of Ca(OH)₂. Group three consisted of three subgroups which were exposed to three different concentrations of combinations of both NaDCC and Ca(OH)₂. The results of the present study show that calcium hydroxide was totally ineffective at all concentrations and NaDCC was effective and also the combination of both was shown to be effective. NaDCC alone was effective at all concentrations and the combination with Ca(OH)₂ was found to be less effective. Ca(OH)₂ was totally ineffective.

The effect of calcium hydroxide, alkali dilution and calcium concentration in mitigating the alkali silica reaction using palm oil fuel ash

NASA Astrophysics Data System (ADS)

Asrah, Hidayati; Mirasa, Abdul Karim; Bolong, Nurmin

2018-02-01

This study investigated the mechanism of how POFA mitigated the ASR expansion. Two types of POFA; the UPOFA and GPOFA with different fineness were used to replace the cement at 20% and 40% and their effects on the mortar bar expansion, calcium hydroxide, alkali dilution, and calcium concentration were investigated. The results showed that UPOFA has a significant ability to mitigate the ASR, even at a lower level of replacement (20%) compared to GPOFA. The mechanism of UPOFA in mitigating the ASR expansion was through a reduction in the calcium hydroxide content, which produced low calcium concentration within the mortar pore solution. Low pore solution alkalinity signified that UPOFA had good alkali dilution effect. Meanwhile, a higher dosage of GPOFA was required to mitigate the ASR expansion. An increase in the pore solution alkalinity of GPOFA mortar indicated higher penetration of alkalis from the NaOH solution, which reduced the alkali dilution effect. However, this was compensated by the increase in the cement dilution effect at higher GPOFA replacement, which controlled the mortar bar expansion below the ASTM limit.

Calcium Hydroxide-induced Proliferation, Migration, Osteogenic Differentiation, and Mineralization via the Mitogen-activated Protein Kinase Pathway in Human Dental Pulp Stem Cells.

PubMed

Chen, Luoping; Zheng, Lisha; Jiang, Jingyi; Gui, Jinpeng; Zhang, Lingyu; Huang, Yan; Chen, Xiaofang; Ji, Jing; Fan, Yubo

2016-09-01

Calcium hydroxide has been extensively used as the gold standard for direct pulp capping in clinical dentistry. It induces proliferation, migration, and mineralization in dental pulp stem cells (DPSCs), but the underlying mechanisms are still unclear. The aim of this study was to investigate the role of the mitogen-activated protein (MAP) kinase pathway in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Human DPSCs between passages 3 and 6 were used. DPSCs were preincubated with inhibitors of MAP kinases and cultured with calcium hydroxide. The phosphorylated MAP kinases were detected by Western blot analysis. Cell viability was analyzed via the methylthiazol tetrazolium assay. Cell migration was estimated using the wound healing assay. Alkaline phosphatase (ALP) expression was analyzed using the ALP staining assay. Mineralization was studied by alizarin red staining analysis. Calcium hydroxide significantly promoted the phosphorylation of the c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase. The inhibition of JNK and p38 signaling abolished calcium hydroxide-induced proliferation of DPSCs. The inhibition of JNK, p38, and extracellular signal-regulated kinase signaling suppressed the migration, ALP expression, and mineralization of DPSCs. Our study showed that the MAP kinase pathway was involved in calcium hydroxide-induced proliferation, migration, osteogenic differentiation, and mineralization in human DPSCs. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of mineral trioxide aggregate (MTA) versus calcium hydroxide cement (Dycal(®) ) in the formation of a dentine bridge: a randomised controlled trial.

PubMed

Leye Benoist, Fatou; Gaye Ndiaye, Fatou; Kane, Abdoul Wakhabe; Benoist, Henri Michel; Farge, Pierre

2012-02-01

To assess the effectiveness of mineral trioxide aggregate (MTA) used as an indirect pulp-capping material in human molar and premolar teeth. We conducted a clinical evaluation of 60 teeth, which underwent an indirect pulp-capping procedure with either MTA or calcium hydroxide cement (Dycal(®) ). Calcium hydroxide was compared with MTA and the thickness of the newly formed dentine was measured at regular time intervals. The follow-up was at 3 and 6 months, and dentine formation was monitored by radiological measurements on digitised images using Mesurim Pro(®) software. At 3 months, the clinical success rates of MTA and calcium hydroxide were 93% and 73%, respectively (P = 0.02). At 6 months, the success rate was 89.6% with MTA, and remained steady at 73% with calcium hydroxide (P = 0.63). The mean initial residual dentine thickness was 0.23 mm, and increased by 0.121 mm with MTA and by 0.136 mm with calcium hydroxide at 3 months. At 6 months, there was an increase of 0.235 mm with MTA and of 0.221 mm with calcium hydroxide.   A higher success rate was observed in the MTA group relative to the Dycal(®) group after 3 months, which was statistically significant. After 6 months, no statistically significant difference was found in the dentine thickness between the two groups. Additional histological investigations are needed to support these findings. © 2012 FDI World Dental Federation.

Efficacy of calcium oxide and calcium hydroxide nanoparticles on the elimination of Enterococcus faecalis in human root dentin.

PubMed

Louwakul, Phumisak; Saelo, Attapon; Khemaleelakul, Saengusa

2017-04-01

The objective of this study was to compare the antibacterial effect of calcium oxide nanoparticles (CONPs) and calcium hydroxide nanoparticles (CHNPs) against Enterococcus faecalis in a dentinal block model. E. faecalis strain JCM 7783 was introduced into dentinal tubules of semicylindrical dentin specimens by centrifugation and incubated for 1 week. Fifty microliters of CONPs or CHNPs was placed on the root canal side of the infected dentin specimens. The specimens were then incubated in aerobic condition at 37 °C and 100 % relative humidity for 1 week. The treated dentin specimens were subjected to fluorescent staining and confocal laser scanning microscopy (CLSM) to analyze the proportions of non-vital and vital bacterial cells inside the dentinal tubules. Scanning electron microscopy (SEM) was used to confirm the effect of the medicaments on the bacteria in the dentinal tubules. Calcium oxide (CO) and calcium hydroxide (CH) were used as controls. Based on the CLSM and SEM analyses, CHNPs were more efficient than CONPs in the elimination of the bacteria in the dentinal tubules. CONPs significantly killed more E. faecalis than CO and CH (P < .05). Neither CO nor CH was able to kill the bacteria. CHNPs were more effective than CONPs in the elimination of E. faecalis in dentinal tubules. CHNPs are effective nanoparticles in killing endodontic bacteria present in dentinal tubules. They have potential as an intracanal medicament, which may be beneficial in root canal therapy.

Improving the quality of rice straw by urea and calcium hydroxide on rumen ecology, microbial protein synthesis in beef cattle.

PubMed

Polyorach, S; Wanapat, M

2015-06-01

Four rumen-fistulated beef cattle were randomly assigned to four treatments according to a 4 × 4 Latin square design to study the influence of urea and calcium hydroxide [Ca(OH)2 ] treatment of rice straw to improve the nutritive value of rice straw. Four dietary treatments were as follows: untreated rice straw, 50 g/kg urea-treated rice straw, 20 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw and 30 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw. All animals were kept in individual pens and fed with concentrate at 0.5 g/kg of BW (DM), rice straw was fed ad libitum. The experiment was conducted for four periods, and each period lasted for 21 days. During the first 14 days, DM feed intake measurements were made while during the last 7 days, all cattle were moved to metabolism crates for total faeces and urine collections. The results revealed that 20 g/kg urea + 20 g/kg calcium hydroxide-treated rice straw improved the nutritive value of rice straw, in terms of dry matter intake, digestibility, ruminal volatile fatty acids, population of bacteria and fungi, nitrogen retention and microbial protein synthesis. Based on this study, it could be concluded that using urea plus calcium hydroxide was one alternative method to improve the nutritive value of rice straw, rumen ecology and fermentation and thus a reduction of treatment cost. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

Chlorhexidine Prevents Root Dentine Mineral Loss and Fracture Caused by Calcium Hydroxide over Time

PubMed Central

Thomaz, Érika Bárbara Abreu Fonseca; Lima, Darlon Martins; Bauer, José

2017-01-01

Purpose. To evaluate the mineral ion loss of root dentine after treatment with 2% chlorhexidine solution (CHX) and to compare its yield and flexural strength (fs) after exposure to calcium hydroxide [Ca(OH)2]. Materials and Methods. Dentine bars (DB) were made from 90 roots of bovine incisors and randomized into three groups: GControl: distilled/deionized water (DDW), GNaOCl: 2.5% sodium hypochlorite + 17% EDTA, and GCHX: CHX + DDW. The release of phosphate (PO4) and calcium (Ca) ions was measured by spectrophotometry. The DB were exposed to Ca(OH)2 paste for 0, 30, 90, and 180 days. DB were subjected to the three-point bending test to obtain yield and fs values. The fracture patterns were evaluated (20x). Data were analyzed using Kruskal-Wallis and Dunn's post hoc tests or one- and two-way ANOVA followed by Tukey's post hoc test (α = 0.05). Results. GCHX showed lower PO43− and Ca2+ ionic release than GNaOCl (p < 0.001). For yield and fs, GCHX > GNaOCl in all periods (p < 0.001), except for yield strength values on 90 days (p = 0.791). A larger frequency of vertical fractures was observed in GNaOCl and that of oblique fractures in GCHX (p < 0.05). Conclusions. CHX prevented PO43− and Ca2+ loss and showed a tendency to preserve the yield and fs of root dentine over time following exposure to Ca(OH)2 paste. PMID:28539937

Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs.

PubMed

Soares, Janir Alves; Leonardo, Mario Roberto; da Silva, Léa Assed Bezerra; Tanomaru Filho, Mario; Ito, Izabel Yoko

2006-01-01

This study aimed at evaluating the antisepsis of the root canal system (RCS) and periapical region (PR) provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. Chronic periapical lesions were induced in 26 pre-molar roots in two dogs. After microbiological sampling, automatic instrumentation using the Profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% EDTA followed by profuse irrigation with physiological saline were carried out in 18 root canals. After drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. After 21 days, the medication was removed, leaving the root canals empty and coronally sealed. After 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the Brown & Brenn method. Eight untreated root canals represented the control group (C-G). Based on the Mann-Whitney test at a confidence level of 5% (p < 0.05), the procedures of antisepsis used offered significant efficacy (p < 0.05) resulting in 100.0% of the canals free of microorganisms. In the C-G, an elevated incidence of various microbial morphotypes was confirmed in all sites of the RCS, with the presence of microbial colonies in the periapical region. In contrast, the experimental group showed a similar pattern of infection in the RCS, although less intense and a reduced level of periapical infection (p < 0.05). It was concluded that adequate instrumentation followed by the application of calcium hydroxide + chlorhexidine offered significant elimination of microorganisms.

Calcium hydroxide as a processing base in alkali-aided pH-shift protein recovery process.

PubMed

Paker, Ilgin; Jaczynski, Jacek; Matak, Kristen E

2017-02-01

Protein may be recovered by using pH shifts to solubilize and precipitate protein. Typically, sodium hydroxide is used as the processing base; however, this has been shown to significantly increase sodium in the final recovered protein. Protein was extracted from black bullhead catfish (Ameiurus melas) using a pH-shift method. Protein was solubilized using either sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH) 2 ) and precipitated at pH 5.5 using hydrochloric acid (HCl). Protein solubility was greater when Ca(OH) 2 was used compared to NaOH during this process. Using Ca(OH) 2 as the processing base yielded the greatest lipid recovery (P < 0.05) at 77 g 100 g -1 , whereas the greatest (P < 0.05) protein recovery yield was recorded as 53 g 100 g -1 protein using NaOH. Protein solubilized with Ca(OH) 2 had more (P < 0.05) calcium in the protein fraction, whereas using NaOH increased (P < 0.05) sodium content. Results of our study showed that protein solubility was increased and the recovered protein had significantly more calcium when Ca(OH) 2 was used as the processing base. Results showed both NaOH and Ca(OH) 2 to be an effective processing base for pH-shift protein recovery processes. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Regenerative endodontic treatment (revascularization) of immature necrotic molars medicated with calcium hydroxide: a case series.

PubMed

Cehreli, Zafer C; Isbitiren, Beste; Sara, Sezgi; Erbas, Gizem

2011-09-01

Revascularization is an emerging regenerative treatment protocol with little published data available in immature molar teeth. The present case series demonstrates the outcome of revascularization treatment with intracanal medicament of calcium hydroxide in immature necrotic molars. Immature necrotic permanent first molars (n = 6) of patients 8-11 years old were treated by a revascularization protocol that used 2.5% NaOCl irrigation, medication with calcium hydroxide placed in the coronal third of the root canals, induction of apical bleeding, and coronal sealing with white mineral trioxide aggregate. Among the treated teeth, 4 molars had undergone prior root canal instrumentation by the referring dentists. National Institutes of Health Image-J program with TurboReg plug-in was used for standardization of the radiographs and to determine the increase in root length and root width. After a follow-up period of 10 months, all teeth demonstrated radiographic evidence of complete periapical healing, progressive thickening of dentinal walls, and continued apical development in the absence of clinical symptoms. Two uninstrumented molars showed a positive response to cold testing at 9 months. On the basis of a follow-up period of 10 months, the present cases demonstrate a favorable outcome of the revascularization procedure in immature necrotic molars by using calcium hydroxide medication in the coronal third of the root canals. Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Histological analysis of the biocompatibility of calcium hydroxide associated with a new vehicle.

PubMed

Simi Junior, Jacy; Machado, Ricardo; Souza, Cássio José Alves de; Loyola, Adriano Motta; Vansan, Luiz Pascoal; Antoniazzi, João Humberto

2015-01-01

Several substances have been researched to act as vehicles associated with calcium hydroxide. The specific type of vehicle is directly related to the effectiveness of the ionic dissociation, antimicrobial action, and biocompatibility of this medication. To make a histological evaluation of the biocompatibility of calcium hydroxide associated with a new vehicle (triethanolamine), compared with polyethylene glycol, saline solution, and olive oil. Fifty mice of guinea pig species were randomly divided into five groups (n = 10) according to each vehicle used--Group 1: calcium hydroxide, Group 2: triethanolamine, Group 3: polyethylene glycol, Group 4: saline solution, and Group 5: olive oil--and further divided into subgroups according to the two analysis periods--(a) 30 and (b) 90 days. Teflon carriers filled with the evaluated substances were placed in standardized bone cavities in the anterior mandible region. The animals were euthanized to perform a histological analysis after the time periods analyzed. In 30 days, specimens from Groups 1, 3, and 5 showed a very pronounced inflammatory response. Specimens from Group 2 showed an inflammatory reaction ranging from mild to severe, with rapid resorption of the material and progressive advancement of osteoid tissue into the teflon carriers. Specimens from Group 4 showed a moderate inflammatory reaction. In 90 days, specimens from Group 1 showed a very pronounced fibrous replacement. In regard to Group 2 specimens, the tested material was solubilized and replaced by newly formed bone tissue. For Groups 3 and 5 specimens, the inflammatory reaction went from acute to moderate. In relation to Group 4 specimens, an organized bone formation process was observed. Specimens from Group 2 showed higher biocompatibility, especially as compared with the specimens from Groups 3 and 5.

Determination of the bactericidal activity of different calcium hydroxide presentations on a dentin model.

PubMed

Sinan, A; Adou, A J; Rochd, T; Calas, P

2007-03-01

Calcium hydroxide placed as a temporary dressing in the root canal helps sterilize infected canals. Hycal and Roeko calcium hydroxide points are two delayed-action medications containing Ca(OH)2 recommended for root canal treatment. The purpose of this study was to test their bactericidal activity in comparison with that of C-PMCP on Streptococcus sanguins strain NCTC 7823. Artificially infected 4-mm high blocks of dentin obtained from bovine incisors were used as an experimental model (n = 192). After three days of treatment with the two antiseptics, intracanal dentin powder was collected by serial drillings and used to inoculate a culture broth. The turbidity of this broth after 24 hours showed if the bacteria were eliminated or not and was used as criterion of antiseptic efficacy. No bacterial growth was observed in the samples treated with C-PMCP. Hycal had a considerable bactericidal activity with 94% of negative cultures whereas first-generation Roeko points had no activity on the strain of S. sanguis tested.

Residual antibacterial activity of chlorhexidine digluconate and camphorated p-monochlorophenol in calcium hydroxide-based root canal dressings.

PubMed

Soares, Janir Alves; Leonardo, Mario Roberto; Tanomaru Filho, Mário; Silva, Léa Assed Bezerra da; Ito, Izabel Yoko

2007-01-01

The purpose of this study was to evaluate the residual antibacterial activity of several calcium hydroxide [Ca(OH)2]-based pastes, placed in root canals of dogs' teeth with induced chronic periapical lesions. Root canals were instrumented with the ProFile rotary system and filled with 4 pastes: G1 (n=16): Ca(OH)2 paste + anesthetic solution; G2 (n=20): Calen paste + camphorated p-monochlorophenol (CMCP); G3 (n=18): Calen; and G4 (n=18): Ca(OH)2 paste + 2% chlorhexidine digluconate. After 21 days, the pastes were removed with size 60 K-files and placed on Petri plates with agar inoculated with Micrococcus luteus ATCC 9341. Pastes that were not placed into root canals served as control. After pre-diffusion, incubation and optimization, the inhibition zones of bacterial growth were measured and analyzed by Mann-Whitney U test at 5% significance level. All pastes showed residual antibacterial activity. The control samples had larger halos (p<0.05). The mean residual antibacterial activity halos in G1, G2, G3 and G4 were 7.6; 10.4; 17.7 and 21.4 mm, respectively. The zones of bacterial growth of G4 were significantly larger than those of G1 and G2 (p<0.05). In conclusion, regardless of the vehicle and antiseptic, all Ca(OH)2-based pastes showed different degrees of measurable residual antibacterial activity. Furthermore, unlike CMCP, chlorhexidine increased significantly the antibacterial activity of Ca(OH)2.

Ion release and mechanical properties of calcium silicate and calcium hydroxide materials used for pulp capping.

PubMed

Natale, L C; Rodrigues, M C; Xavier, T A; Simões, A; de Souza, D N; Braga, R R

2015-01-01

To compare the ion release and mechanical properties of a calcium hydroxide (Dycal) and two calcium silicate (MTA Angelus and Biodentine) cements. Calcium and hydroxyl ion release in water from 24-h set cements were calculated from titration with HCl (n = 3). Calcium release after 7, 14, 21 and 28 days at pH 5.5 and 7.0 was measured using ICP-OES (n = 6). Flexural strength (FS) and modulus (E) were tested after 48-h storage, and compressive strength (CS) was tested after 48 h and 7 days (n = 10). Ion release and mechanical data were subjected to anova/Tukey and Kruskal-Wallis/Mann-Whitney tests, respectively (α = 0.05). Titration curves revealed that Dycal released significantly fewer ions in solution than calcium silicates (P < 0.001). Calcium release remained constant at pH 7.0, whilst at pH 5.5, it dropped significantly by 24% after 21 days (P < 0.05). At pH 5.5, MTA Angelus released significantly more calcium than Dycal (P < 0.01), whilst Biodentine had superior ion release than Dycal at pH 7.0 (P < 0.01). Biodentine had superior flexural strength, flexural modulus and compressive strength than the other cements, whilst MTA Angelus had higher modulus than Dycal (P < 0.001). Immediate calcium and hydroxyl ion release in solution was significantly lower for Dycal. In general, all materials released constant calcium levels over 28 days, but release from Dycal was significantly lower than Biodentine and MTA Angelus depending on pH conditions. Biodentine had substantially higher strength and modulus than MTA Angelus and Dycal, both of which demonstrated low stress-bearing capabilities. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer.

PubMed

Kuga, Milton Carlos; Duarte, Marco Antonio Hungaro; Sant'anna-Júnior, Arnaldo; Keine, Kátia Cristina; Faria, Gisele; Dantas, Andrea Abi Rached; Guiotti, Flávia Angélica

2014-06-01

Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.

Accidental injury of the inferior alveolar nerve due to the extrusion of calcium hydroxide in endodontic treatment: a case report

PubMed Central

2016-01-01

During clinical endodontic treatment, we often find radiopaque filling material beyond the root apex. Accidental extrusion of calcium hydroxide could cause the injury of inferior alveolar nerve, such as paresthesia or continuous inflammatory response. This case report presents the extrusion of calcium hydroxide and treatment procedures including surgical intervention. A 48 yr old female patient experienced Calcipex II extrusion in to the inferior alveolar canal on left mandibular area during endodontic treatment. After completion of endodontic treatment on left mandibular first molar, surgical intervention was planned under general anesthesia. After cortical bone osteotomy and debridement, neuroma resection and neurorrhaphy was performed, and prognosis was observed. But no improvement in sensory nerve was seen following surgical intervention after 20 mon. A clinician should be aware of extrusion of intracanal medicaments and the possibility of damage on inferior alveolar canal. Injectable type of calcium hydroxide should be applied with care for preventing nerve injury. The alternative delivery method such as lentulo spiral was suggested on the posterior mandibular molar. PMID:26877992

Water sorption and solubility of different calcium hydroxide cements.

PubMed

Francisconi, Luciana Fávaro; de Freitas, Anderson Pinheiro; Scaffa, Polliana Mendes Candia; Mondelli, Rafael Francisco Lia; Francisconi, Paulo Afonso Silveira

2009-01-01

Calcium hydroxide cements have been largely used in deep cavities due to their abilities to stimulate dentin formation. However, their resistance can be relatively low and their solubility relatively high, in many instances. This study evaluated water sorption and solubility of different calcium hydroxide cements, in order to show alterations that may reduce their effectiveness. Five discs (20 mm in diameter and 1.5 mm thick) of three different materials (Biocal, Dycal and Hidro C) were prepared with the aid of a ring-shaped metallic matrix. After being stored at 37 degrees C for 24 h, the discs were weighed on a precision weight scale, dehydrated and weighed again. Immediately after weighing, discs were stored for a week in 50 mL of distilled water at 37 degrees C and, then, weighed again, dehydrated and submitted to a new weighing. The loss of soluble material and its water sorption was obtained from the difference between the initial and the final dry mass of each disc, after 1 week of immersion in water. Data were analyzed for significant differences by two-way ANOVA and Tukey's test (p<0.05). Mean water sorption values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.006 +/- 0.001 / 2.15); Dycal (0.016 +/- 0.004 / 5.49); and Hidro C (0.025 +/- 0.003 / 8.27). Mean solubility values (g) +/- standard deviation and percentage (%), for each evaluated cement, were: Biocal (0.002 +/- 0.001 / 0.72); Dycal (0.013 +/- 0.004 / 4.21); and Hidro C (0.023 +/- 0.004 / 7.65). Biocal absorbed less water and was less soluble than the other evaluated cements; Hidro C exhibited the highest water sorption and solubility values; and there were significant differences among all evaluated experimental groups.

The Efficacy of Calcium Hydroxide Powder mixed with 0.2% Chlorhexidine Digluconate or mixed with Normal Saline as Intracanal Medicament in the Treatment of Apical Periodontitis.

PubMed

Menakaya, Ifeoma N; Adegbulugbe, Ilemobade C; Oderinu, Olabisi H; Shaba, Olufemi P

2015-08-01

To compare the efficacy of calcium hydroxide powder mixed with 0.2% chlorhexidine digluconate or mixed with normal saline as intracanal medicament in the treatment of apical periodontitis. Subjects were 55 in number aged 17 to 60 years. Two-visit conventional root canal treatment was performed on 70 teeth. The teeth were divided by randomization (balloting) into two groups: control group and experimental group, each with 35 teeth treated with calcium hydroxide mixed with normal saline or with 0.2% chlorhexidine digluconate as intracanal medicament respectively. All treated teeth were evaluated clinically and radiographically for signs and symptom of periapical infection at specified periods postoperatively. Overall efficacy of medicament was rated based on quality guidelines for endodontic treatment by the European Society of Endodontology 2006. A postoperative favorable outcome of 97.1% in the control group and 94.3% in the experimental group was observed at 6-month review. This difference was not statistically significant (p > 0.05). The use of normal saline or 0.2% chlorhexidine digluconate to mix calcium hydroxide used as intracanal medicament during endodontic treatment resulted in high postoperative favorable outcomes. Efficacy of 0.2% chlorhexidine digluconate as a vehicle for mixing calcium hydroxide as an intracanal medicament in the treatment of apical periodontitis is comparable to the efficacy of calcium hydroxide mixed with normal saline.

Microbial evaluation of traumatized teeth treated with triple antibiotic paste or calcium hydroxide with 2% chlorhexidine gel in pulp revascularization.

PubMed

Nagata, Juliana Y; Soares, Adriana J; Souza-Filho, Francisco J; Zaia, Alexandre A; Ferraz, Caio C R; Almeida, José F A; Gomes, Brenda P F A

2014-06-01

Revascularization outcome depends on microbial elimination because apical repair will not happen in the presence of infected tissues. This study evaluated the microbial composition of traumatized immature teeth and assessed their reduction during different stages of the revascularization procedures performed with 2 intracanal medicaments. Fifteen patients (7-17 years old) with immature teeth were submitted to the revascularization procedures; they were divided into 2 groups according to the intracanal medicament used: TAP group (n = 7), medicated with a triple antibiotic paste, and CHP group (n = 8), dressed with calcium hydroxide + 2% chlorhexidine gel. Samples were taken before any treatment (S1), after irrigation with 6% NaOCl (S2), after irrigation with 2% chlorhexidine (S3), after intracanal dressing (S4), and after 17% EDTA irrigation (S5). Cultivable bacteria recovered from the 5 stages were counted and identified by means of polymerase chain reaction assay (16S rRNA). Both groups had colony-forming unit counts significantly reduced after S2 (P < .05); however, no significant difference was found between the irrigants (S2 and S3, P = .99). No difference in bacteria counts was found between the intracanal medicaments used (P = .95). The most prevalent bacteria detected were Actinomyces naeslundii (66.67%), followed by Porphyromonas endodontalis, Parvimonas micra, and Fusobacterium nucleatum, which were detected in 33.34% of the root canals. An average of 2.13 species per canal was found, and no statistical correlation was observed between bacterial species and clinical/radiographic features. The microbial profile of infected immature teeth is similar to that of primarily infected permanent teeth. The greatest bacterial reduction was promoted by the irrigation solutions. The revascularization protocols that used the tested intracanal medicaments were efficient in reducing viable bacteria in necrotic immature teeth. Copyright © 2014 American Association of

Effects of calcium hydroxide addition on the physical and chemical properties of a calcium silicate-based sealer

PubMed Central

KUGA, Milton Carlos; DUARTE, Marco Antonio Hungaro; SANT'ANNA-JÚNIOR, Arnaldo; KEINE, Kátia Cristina; FARIA, Gisele; DANTAS, Andrea Abi Rached; GUIOTTI, Flávia Angélica

2014-01-01

Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). Results In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. Conclusions The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential. PMID:25025558

Effects of zinc oxide-eugenol and calcium hydroxide/ iodoform on delaying root resorption in primary molars without successors.

PubMed

Lin, Bichen; Zhao, Yuming; Yang, Jie; Wang, Wenjun; Ge, Li-hong

2014-01-01

The purpose of this study was to compare the effects of zinc oxide-eugenol (ZOE) and calcium hydroxide/iodoform paste (Vitapex), as root canal filling materials in pulpectomy, on delaying the root resorption of primary molars without permanent successors. Animal models without permanent successors were surgically established in beagle dogs. Root resorption was observed via periapical radiographs. The onset of root resorption of primary mandibular molars without successors occurred later (p<0.05) than physiologic resorption. ZOE pulpectomy clearly delayed the root resorption of primary molars without permanent successors (p<0.05), whereas resorption of primary molars with Vitapex pulpectomy started at almost the same time as physiologic resorption. Compared with Vitapex, ZOE was a more effective root canal filling material in delaying the root resorption of primary molars.

Ion Association versus Ion Interaction Models in Examining Electrolyte Solutions: Application to Calcium Hydroxide Solubility Equilibrium

ERIC Educational Resources Information Center

Menéndez, M. Isabel; Borge, Javier

2014-01-01

The heterogeneous equilibrium of the solubility of calcium hydroxide in water is used to predict both its solubility product from solubility and solubility values from solubility product when inert salts, in any concentration, are present. Accepting the necessity of including activity coefficients to treat the saturated solution of calcium…

Nanoparticles for cultural heritage conservation: calcium and barium hydroxide nanoparticles for wall painting consolidation.

PubMed

Giorgi, Rodorico; Ambrosi, Moira; Toccafondi, Nicola; Baglioni, Piero

2010-08-16

Nanotechnology provides new concepts and materials for the consolidation and protection of wall paintings. In particular, humble calcium and barium hydroxide nanoparticles offer a versatile and highly efficient tool to combat the main degradation processes altering wall paintings. Clear example of the efficacy and potentiality of nanotechnology is represented by the conservation in situ of Maya wall paintings in the archaeological area in Calakmul (Mexico).

WATER SORPTION AND SOLUBILITY OF DIFFERENT CALCIUM HYDROXIDE CEMENTS

PubMed Central

Francisconi, Luciana Fávaro; de Freitas, Anderson Pinheiro; Scaffa, Polliana Mendes Candia; Mondelli, Rafael Francisco Lia; Francisconi, Paulo Afonso Silveira

2009-01-01

Objectives: Calcium hydroxide cements have been largely used in deep cavities due to their abilities to stimulate dentin formation. However, their resistance can be relatively low and their solubility relatively high, in many instances. This study evaluated water sorption and solubility of different calcium hydroxide cements, in order to show alterations that may reduce their effectiveness. Material and methods: Five discs (20 mm in diameter and 1.5 mm thick) of three different materials (Biocal®, Dycal® and Hidro C®) were prepared with the aid of a ring-shaped metallic matrix. After being stored at 37°C for 24 h, the discs were weighed on a precision weight scale, dehydrated and weighed again. Immediately after weighing, discs were stored for a week in 50 mL of distilled water at 37°C and, then, weighed again, dehydrated and submitted to a new weighing. The loss of soluble material and its water sorption was obtained from the difference between the initial and the final dry mass of each disc, after 1 week of immersion in water. Data were analyzed for significant differences by two-way ANOVA and Tukey's test (p<0.05). Results: Mean water sorption values (g) ± standard deviation and percentage (%), for each evaluated cement, were: Biocal® (0.006 ± 0.001 / 2.15); Dycal® (0.016 ± 0.004 / 5.49); and Hidro C® (0.025 ± 0.003 / 8.27). Mean solubility values (g) ± standard deviation and percentage (%), for each evaluated cement, were: Biocal® (0.002 ± 0.001 / 0.72); Dycal® (0.013 ± 0.004 / 4.21); and Hidro C® (0.023 ± 0.004 / 7.65). Conclusions: Biocal® absorbed less water and was less soluble than the other evaluated cements; Hidro C® exhibited the highest water sorption and solubility values; and there were significant differences among all evaluated experimental groups. PMID:19936520

Critical review: Injectability of calcium phosphate pastes and cements.

PubMed

O'Neill, R; McCarthy, H O; Montufar, E B; Ginebra, M-P; Wilson, D I; Lennon, A; Dunne, N

2017-03-01

Calcium phosphate cements (CPC) have seen clinical success in many dental and orthopaedic applications in recent years. The properties of CPC essential for clinical success are reviewed in this article, which includes properties of the set cement (e.g. bioresorbability, biocompatibility, porosity and mechanical properties) and unset cement (e.g. setting time, cohesion, flow properties and ease of delivery to the surgical site). Emphasis is on the delivery of calcium phosphate (CaP) pastes and CPC, in particular the occurrence of separation of the liquid and solid components of the pastes and cements during injection; and established methods to reduce this phase separation. In addition a review of phase separation mechanisms observed during the extrusion of other biphasic paste systems and the theoretical models used to describe these mechanisms are discussed. Occurrence of phase separation of calcium phosphate pastes and cements during injection limits their full exploitation as a bone substitute in minimally invasive surgical applications. Due to lack of theoretical understanding of the phase separation mechanism(s), optimisation of an injectable CPC that satisfies clinical requirements has proven difficult. However, phase separation of pastes during delivery has been the focus across several research fields. Therefore in addition to a review of methods to reduce phase separation of CPC and the associated constraints, a review of phase separation mechanisms observed during extrusion of other pastes and the theoretical models used to describe these mechanisms is presented. It is anticipated this review will benefit future attempts to develop injectable calcium phosphate based systems. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Effect of calcium hydroxide application to feedlot pen surface material on ammonia, odor, and greenhouse gas emissions

USDA-ARS?s Scientific Manuscript database

Calcium hydroxide (lime) is used to reduce microorganisms and odors in human biosolids, animal and poultry manures, and abattoir wastes. In the cattle industry, lime has been used as a disinfectant and is spread on the pen surface to control infections such as diarrhea and foot rot. The increase in ...

Nonsurgical Treatment of Two Periapical Lesions with Calcium Hydroxide Using Two Different Vehicles

PubMed Central

Dixit, Seema; Dixit, Ashutosh; Kumar, Pravin

2014-01-01

Calcium hydroxide is used extensively as an intracanal medicament in endodontics for many years. It is used in various clinical situations such as to promote apexification, to repair perforation, to enhance healing of periapical lesions, to control root resorption, and to control exudation in teeth with persistent periapical inflammation. This paper presents a case report in which Ca(OH)2 was used as an intracanal medicament for treatment of periradicular lesions using two different vehicles in two different teeth of same patient. PMID:25133000

Assessment of the Pozzolanic Activity of a Spent Catalyst by Conductivity Measurement of Aqueous Suspensions with Calcium Hydroxide

PubMed Central

Velázquez, Sergio; Monzó, José M.; Borrachero, María V.; Payá, Jordi

2014-01-01

The pozzolanic activity of the spent catalyst produced by fluid catalytic cracking (FCC) has been studied by various methods in recent years. However, no quick and easy method has been reported for this activity based on the associated studies. In this work, the pozzolanic activity of a spent catalyst was investigated by measuring its electrical conductivity in aqueous suspensions of pozzolan/calcium hydroxide. The behavior of the FCC catalyst residue was compared to that of reactive and inert materials of similar chemical compositions. Further, the influence of temperature on the suspension was studied, and also, a new method was proposed in which the pozzolan/calcium hydroxide ratio was varied (with the initial presence of solid Ca(OH)2 in the system). It was concluded that the method is effective, fast and simple for evaluating the high reactivity of the catalyst. Therefore, this method is an alternative for the evaluation of the reactivity of pozzolanic materials. PMID:28788583

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide.

PubMed

Sazwi, Nordin Nur; Nalina, Thurairajah; Abdul Rahim, Zubaidah Haji

2013-12-11

Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682). The betel quid has higher TPC, and antioxidant and

Zinc oxide eugenol paste jeopardises the adhesive bonding to primary dentine.

PubMed

Pires, C W; Lenzi, T L; Soares, F Z M; Rocha, R O

2018-05-12

This was to evaluate the influence of root canal filling pastes on microshear bond strength (µSBS) of an adhesive system to primary dentine. Human (32) primary molars were randomly assigned into four experimental groups (n = 8): zinc oxide eugenol paste (ZOE); iodoform paste (Guedes-Pinto paste); calcium hydroxide paste thickened with zinc oxide; and no filling paste (control). Flat dentine surfaces were covered with a 1 mm-thick layer of the pastes for 15 min at 37 °C. The pastes were mechanically removed from dentine surfaces, followed by rinsing and drying. After adhesive application (Adper Single Bond 2, 3M ESPE), starch tubes were placed over pre-treated dentine and filled with composite resin (Z250, 3M ESPE). The µSBS test was performed after 24 h of water storage at 37 °C. The failure mode was evaluated using a stereomicroscope. The µSBS values (MPa) were analysed with one-way ANOVA and Tukey post-hoc tests (α = 0.05). The lowest µSBS values were achieved when ZOE was used. No difference was found among other filling pastes compared with control group. All specimens showed adhesive/mixed failures. Zinc oxide eugenol paste negatively influenced the bond strength of adhesive systems to primary dentine. Iodoform-based Guedes-Pinto paste and calcium hydroxide paste thickened with zinc oxide did not influence the microshear bond strength values.

In vitro antimicrobial and anti-endotoxin action of Zingiber Officinale as auxiliary chemical and medicament combined to calcium hydroxide and chlorhexidine.

PubMed

Valera, Marcia Carneiro; Cardoso, Flávia Goulart da Rosa; Maekawa, Lilian Eiko; Camargo, Carlos Henrique Ribeiro; de Oliveira, Luciane Dias; Carvalho, Cláudio Antônio Talge

2015-01-01

This study was conducted in vitro to compare the effectiveness of Zingiber Officinale as an auxiliary chemical substance followed by placement of different intra-canal medication in removing endotoxins and cultivable micro-organisms from infected root canals. Seventy-two root canals were contaminated with Enterococcus faecalis, Candida albicans and Escherichia coli for 28 days. After, the teeth were instrumented using Zingiber Officinale and divided into six groups according to the intra-canal medication: chlorhexidine gel; calcium hydroxide + chlorhexidine gel; glycolic ginger extract; calcium hydroxide + glycolic ginger extract; calcium hydroxide + saline solution and saline solution (control). Sample collections were performed after root canal contamination (Baseline; S1), after instrumentation (S2), 7 days after instrumentation (S3), after 14 days with intra-canal medication (S4) and 7 days after removal of intra-canal medication (S5). The results were analyzed by the Kruskal-Wallis and Dunn tests. It was observed that in S2 and S3 there was significant reduction of the micro-organisms and the quantity of endotoxins after instrumentation. In samples S4 and S5 there was complete elimination of micro-organisms and significant reduction of endotoxins. It was concluded that Zingiber Officinale as an auxiliary chemical substance was effective on the micro-organisms tested, yet was unable to eliminate the endotoxins. Similarly, the intra-canal medication were effective on micro-organisms, yet did not completely eliminate the endotoxins.

Formocresol versus calcium hydroxide direct pulp capping of human primary molars: two year follow-up.

PubMed

Aminabadi, Naser Asl; Farahani, Ramin Mostofi Zadeh; Oskouei, Sina Ghertasi

2010-01-01

Clinical and radiographic evaluation of the premedicated direct pulp capping using formocresol (PDC) versus conventional direct pulp capping using calcium hydroxide (CDC) in human carious primary molars. A total of 120 vital primary molars with pinpoint exposure during caries removal in 84 patients aged 4-5 years were selected. In the PDC group (n = 60), 20% Buckley's formocresol solution, and in the CDC group (n = 60), calcium hydroxide powder were applied to the exposure sites followed by placement of zinc oxide-eugenol base. Teeth were restored with preformed stainless steel crowns. Clinical and radiographic evaluations of the treatment outcomes were performed at regular intervals of 6 and 12 months, respectively, for two years post-operatively. The prevalence of spontaneous pain, sensitivity on percussion, and fistula were significantly higher in the CDC group compared to the PDC group (P < 0.05). The number of teeth exhibiting periapical/furcal radiolucency or external/internal root resorption was also higher in the CDC group (P < 0.05). The clinical success rate of the PDC was 90% compared to the 61.7% of the CDC (P < 0.05). The radiographic success rates of the PDC and CDC groups were 85% and 53.3%, respectively (P < 0.05). It seems formocresol premedicated direct pulp capping could safely be used as a substitute for conventional direct pulp capping.

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide

PubMed Central

2013-01-01

Background Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Methods Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Results Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective

Evaluation of effectiveness of various irrigating solutions on removal of calcium hydroxide mixed with 2% chlorhexidine gel and detection of orange-brown precipitate after removal.

PubMed

Arslan, Hakan; Gok, Tuba; Saygili, Gokhan; Altintop, Hülya; Akçay, Merve; Çapar, Ismail Davut

2014-11-01

The aims of the present study were to evaluate the effect of various irrigating solutions on the removal of calcium hydroxide mixed with 2% chlorhexidine gel from an artificial groove created in a root canal and the generation of orange-brown precipitate in the remaining calcium hydroxide mixed with 2% chlorhexidine gel after irrigation with the various irrigating solutions. The root canals of 48 mandibular premolars were prepared using ProTaper Universal Rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and calcium hydroxide mixed with 2% chlorhexidine gel medicament was placed into the grooves. The roots were randomly divided into 4 experimental groups specified by the irrigation solution used: 1% NaOCl, 17% EDTA, 7% maleic acid, and 10% citric acid (n = 12). The amount of remaining medicament was evaluated under a stereomicroscope using a 4-grade scoring system. After irrigation, the specimens were also evaluated for the presence/absence of orange-brown precipitate. The effects of the different irrigation solutions on medicament removal were statistically evaluated using the Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction at a 95% confidence level (P = .0083). Solutions of 7% maleic acid and 10% citric acid were superior to solutions of 1% NaOCl and 17% EDTA in removing calcium hydroxide mixed with 2% chlorhexidine gel (P < .0083). There were no significant differences among the other groups (P > .0083). Orange-brown precipitate was observed in all specimens of the NaOCl group but in no specimens in the other groups. Irrigation solutions of 7% maleic acid and 10% citric acid were more effective in the removal of calcium hydroxide mixed with 2% chlorhexidine gel than those of 1% NaOCl and 17% EDTA. Orange-brown precipitate was found in all specimens of the Na

Polymer coated CaAl-layered double hydroxide nanomaterials for potential calcium supplement.

PubMed

Kim, Tae-Hyun; Lee, Jeong-A; Choi, Soo-Jin; Oh, Jae-Min

2014-12-05

We have successfully prepared layered double hydroxide (LDH) nanomaterials containing calcium and aluminum ions in the framework (CaAl-LDH). The surface of CaAl-LDH was coated with enteric polymer, Eudragit®L 100 in order to protect nanomaterials from fast dissolution under gastric condition of pH 1.2. The X-ray diffraction patterns, Fourier transform infrared spectroscopy, scanning electron and transmission electron microscopy revealed that the pristine LDH was well prepared having hydrocalumite structure, and that the polymer effectively coated the surface of LDH without disturbing structure. From thermal analysis, it was determined that only a small amount (less than 1%) of polymer was coated on the LDH surface. Metal dissolution from LDH nanomaterials was significantly reduced upon Eudragit®L 100 coating at pH 1.2, 6.8 and 7.4, which simulates gastric, enteric and plasma conditions, respectively, and the dissolution effect was the most suppressed at pH 1.2. The LDH nanomaterials did not exhibit any significant cytotoxicity up to 1000 μg/mL and intracellular calcium concentration significantly increased in LDH-treated human intestinal cells. Pharmacokinetic study demonstrated absorption efficiency of Eudragit®L 100 coated LDH following oral administration to rats. Moreover, the LDH nanomaterials did not cause acute toxic effect in vivo. All the results suggest the great potential of CaAl-LDH nanomaterials as a calcium supplement.

pH and calcium ion release evaluation of pure and calcium hydroxide-containing Epiphany for use in retrograde filling

PubMed Central

TANOMARU-FILHO, Mário; SAÇAKI, Juliana Nogueira; FALEIROS, Frederico Bordini Chaves; GUERREIRO-TANOMARU, Juliane Maria

2011-01-01

Objective Hydroxyl (OH-) and calcium (Ca++) ion release was evaluated in six materials: G1) Sealer 26, G2) White mineral trioxide aggregate (MTA), G3) epiphany, G4) epiphany + 10% calcium hydroxide (CH), G5) epiphany + 20% CH, and G6) zinc oxide and eugenol. Material and Methods Specimens were placed in polyethylene tubes and immersed in distilled water. After 3, 6, 12, 24, and 48 h, 7, 14, and 28 days, the water was assessed for pH with a pH meter and for Ca++ release by atomic absorption spectrophotometry. Results G1, G2, G4, and G5 had the highest pH until 14 days (p<0.05). G1 presented the highest Ca++ release until 6 h, and G4 and G5, from 12 h through 14 days. Ca++ release was greater for G1 and G2 at 28 days. G6 released the least Ca++. Conclusion MTA, Sealer 26, epiphany, and epiphany + CH release OH - and Ca++ ions. Epiphany + CH may be an alternative as retrofilling material. PMID:21437461

Histological comparison of alendronate, calcium hydroxide and formocresol in amputated rat molar.

PubMed

Cengiz, S Burcak; Batirbaygil, Yildiz; Onur, Mehmet Ali; Atilla, Pergin; Asan, Esin; Altay, Nil; Cehreli, Zafer C

2005-10-01

The purpose of this study was to evaluate the potential of alendronate sodium (ALN), a biphosohonate to stimulate hard tissue formation in pulpotomized (amputated) rat molars. Two commonly used pulpotomy materials, calcium hydroxide (CH) and formocresol (FC) were utilized for comparisons. Histological evaluations were performed by observers blinded to treatment allocation on days 7, 15, 30 and 60, followed by statistical analysis of selected histological criteria. In all evaluation periods, hard tissue deposition was evident along the radicular dentin in ALN and CH groups. In days 30 and 60, the latter two groups showed no differences in inflammatory cell response and hard tissue deposition scores (P > 0.05). ALN appears to be capable of maintaining pulpal vitality, while promoting hard tissue formation, similar to CH.

Calcium hydroxide nanoparticles for the conservation of cultural heritage: new formulations for the deacidification of cellulose-based artifacts

NASA Astrophysics Data System (ADS)

Poggi, G.; Toccafondi, N.; Melita, L. N.; Knowles, J. C.; Bozec, L.; Giorgi, R.; Baglioni, P.

2014-03-01

Alkaline earth metal hydroxide nanoparticles dispersions have demonstrated to be efficient for the preservation of cellulose-based artifacts, providing a stable neutral environment and, if in excess, turning into mild alkaline species. New formulations tailored for specific conservation issues have been recently obtained via a solvothermal reaction, starting from bulk metal, and short chain alcohols. Using this synthetic procedure, stable, and high concentrated calcium hydroxide nanoparticles dispersions can be obtained. The characterization of nanoparticles was carried out by dynamic light scattering, transmission electron microscopy and X-ray powder diffraction and showed that the dispersed systems are particularly suitable for the application on porous substrates. In a direct application of this technology, acidic paper and canvas samples were artificially aged after deacidification using calcium hydroxide nanoparticles dispersed in short chain alcohols. Cellulose viscosimetric polymerization degree (DPv), cellulose pyrolysis temperature, and samples' pH were evaluated upon the aging and in terms of protective action arising from the applied treatment. In particular, determinations of DPv clearly showed that the degradation of acidic paper and canvas samples proceeds at higher rates with respect to deacidified samples. These evidences were also confirmed by the thermogravimetric analysis of samples, in which the benefits due to the deacidification treatments are measured in terms of pyrolysis temperature of cellulose. These new formulations of nanoparticles dispersions expand the palette of available tools for the conservation of cellulose-based works of art, such as easel paintings, and manuscripts, potentially opening the way for the intervention on parchment and leather, whose preservation is a particularly challenging task.

In vitro study of calcium hydroxide removal from mandibular molar root canals.

PubMed

Ma, Jingzhi; Shen, Ya; Yang, Yan; Gao, Yuan; Wan, Pan; Gan, Yan; Patel, Payal; Curtis, Allison; Khakpour, Mehrzad; Haapasalo, Markus

2015-04-01

Previous studies have shown the difficulty in removing calcium hydroxide (Ca[OH]2) paste from the root canals before root filling. Mesial and distal canals of 30 mandibular molars were prepared with the WaveOne Primary (25/.08) and Large file (40/.08) (Dentsply Tulsa Dental Specialties, Tulsa, OK), respectively. All canals were then filled with Ca(OH)2. The teeth were divided into the following 3 treatment groups (each with n = 10): (1) instrumentation with needle irrigation, (2) instrumentation with irrigation and passive ultrasonic activation (PUI), and (3) the GentleWave system (Sonendo, Inc, Laguna Hills, CA) without instrumentation. The irrigation time in each group was 7.5 minutes. To further test the efficiency of the GentleWave system, shorter times of 90 seconds were tested using water alone. Reconstructed micro-computed tomographic scans were used to measure the volume of the canals and Ca(OH)2 after instrumentation, initial filling of Ca(OH)2, and after its removal. The percentage of Ca(OH)2 remaining in the canals was calculated. None of the 10 teeth (30 canals) in the conventional irrigation and PUI groups were completely cleaned of Ca(OH)2 in 7.5 minutes. In the apical third of mesial and distal canals, respectively, conventional irrigation removed 47.82% ± 16.36% and 77.68% ± 12.82%, PUI removed 61.66% ± 25.54% and 88.85 ± 12.06%, and the GentleWave system removed significantly more Ca(OH)2 (P < .05) with 100% and 98.78% ± 3.84%. Additional experiments in 10 teeth, using only water as the irrigant, revealed that the GentleWave system removed 99.85% and 99.97% of Ca(OH)2 within 90 seconds without the use of any instruments in the mesial and distal canals, respectively. The study confirms the difficulty to remove Ca(OH)2 from root canals using conventional methods. The GentleWave system removed the paste within 90 seconds using water irrigation alone. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights

THE COMPARISON OF SEVERAL STANDARD MATERIALS AND TECHNIQUES FOR THE WARREN-AVERBACH DETERMINATION OF MICRO-STRUCTURE CHARACTERISTICS OF CALCIUM HYDROXIDE SORBENT MATERIALS

EPA Science Inventory

The paper gives results of a comparison of several standard materials and techniques for the Warren-Averbach determination of microstructure characteristics of calcium hydroxide--Ca(OH)2--sorbent materials. The comparison is part of an investigation of the injection of dry Ca(OH)...

In vitro effects of calcium hydroxide and polymyxin B on endotoxins in root canals.

PubMed

Oliveira, L D; Leão, M V P; Carvalho, C A T; Camargo, C H R; Valera, M C; Jorge, A O C; Unterkircher, C S

2005-02-01

To evaluate the effects of intracanal medicaments on endotoxins in root canals. Seventy-five freshly extracted maxillary incisors were used in this study. The crowns of teeth were sectioned near the CEJ in order to standardize the root length to 14 mm. The root canals were instrumented to an apical size #50 file and irrigated with 1% sodium hypochlorite solution and sterilized with 60Co gamma irradiation. Standardized suspension containing Escherichia coli endotoxin was inoculated into the 60 root canals. The specimens were randomly assigned to 5 groups (n=15), according to the intracanal medicament used: (G1) calcium hydroxide; (G2) polymyxin B; (G3) combination neomycin-polymyxin B-hydrocortisone; (G4) positive control (no intracanal medicament); (G5) negative control (no endotoxin and no intracanal medicament). After 7 days, the detoxification of endotoxin was evaluated by Limulus lysate assay and antibody production in B-lymphocytes culture. Groups 1, 2 and 5 presented the best results by Limulus lysate and were significantly different to groups 3 and 4 (p<0.05). Stimulation of antibodies production in cell culture by groups 1 and 6 was smaller and statistically different than groups 2, 3, 4 and 5 (p<0.05). Groups 2 and 5 induced a small increase in the antibodies production in relation to the groups 1 and 6. Groups 3 and 4 induced a significant increase of antibodies production (p<0.05). The calcium hydroxide and polymyxin B intracanal medicaments detoxified endotoxin in root canals and altered the properties of LPS to stimulate the antibody production by B-lymphocytes. The combination neomycin-polymyxin B-hydrocortisone did not detoxified endotoxin.

Precursor preparation for Ca-Al layered double hydroxide to remove hexavalent chromium coexisting with calcium and magnesium chlorides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Lihua; He, Xiaoman; Qu, Jun

Al(OH){sub 3} and Ca(OH){sub 2} powders are co-ground to prepare a precursor which hydrates into a layered double hydroxide (LDH) phase by agitation in aqueous solution with target hexavalent chromium (Cr(VI)) at room temperature, to achieve an obvious improvement in removal efficiency of Cr(VI) through an easy incorporation into the structure. Although the prepared precursor transforms into LDH phases also when agitated in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist. The adsorption isotherm and kinetic studies show that the phenomena occurring on the Al-Ca precursor fit a pseudo-second-order kineticsmore » with a Langmuir adsorption capacity of 59.45 mg/g. Besides, characterizations of the prepared precursor and the samples after adsorption are also performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscope (TEM) to understand the reason of the preferential incorporation of Cr(VI) to the coexisting chloride salts during the LDH phase formation. - Graphical abstract: Activated Ca-Al hydroxides (C{sub 3}A) transformed into Ca-Al-OH compound when agitated in water. Ca-Al precursor (C{sub 3}A) was agitated in a hexavalent chromium (Cr(VI)) solution to form Al-Ca-CrO{sub 4} LDH product. Ca-Al-CrO{sub 4} LDH phase occurred preferentially to Ca-Al-MCl{sub 2} LDH phases in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist. - Highlights: • Activated Ca-Al hydroxides transformed into LDH when agitated in water with some inorganic substances. • Hexavalent Cr was incorporated in the LDH structure at high adsorption capacity. • Ca-Al-Cr LDH phase occurred preferentially to Ca-Al-MCl{sub 2} LDH phases with coexistence. • The prepared Ca-Al hydroxides had high performance as adsorbent even with high salinity of the solution.« less

Novel Injectable Calcium Phosphate Bone Cement from Wet Chemical Precipitation Method

NASA Astrophysics Data System (ADS)

Hablee, S.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.; Singh, R.

2017-06-01

Calcium phosphate cement has been prepared via chemical precipitation method for injectable bone filling materials. Calcium hydroxide, Ca(OH)2, and diammonium hydrogen phosphate, (NH4)2HPO4, were used as calcium and phosphorus precursors respectively. The synthesized powder was mixed with water at different powder-to-liquid (P/L) ratios, which was adjusted at 0.8, 0.9, 1.0, 1.1 and 1.2. The influence of P/L ratio on the injectability, setting time and mechanical strength of calcium phosphate cement paste has been evaluated. The synthesized powder appeared as purely hydroxyapatite with nanosized and agglomerated spherical particles. All cement pastes show excellent injectability except for the paste with P/L ratio 1.2. Calcium phosphate cement with P/L ratio 1.1 shows the ideal cement for bone filler application with good injectability, the initial and final setting times of 30 min and 160 min, and the compression strength of 2.47 MPa. The result indicated that the newly developed calcium phosphate cement is physically suitable for bone filler application. This paper presents our investigation on the effect of P/L ratio on the handling and mechanical properties of calcium phosphate cement prepared via wet chemical precipitation method.

Preparation of calcium- and magnesium-fortified potato starches with altered pasting properties.

PubMed

Noda, Takahiro; Takigawa, Shigenobu; Matsuura-Endo, Chie; Ishiguro, Koji; Nagasawa, Koichi; Jinno, Masahiro

2014-09-15

Calcium- and magnesium-fortified potato starches were prepared by immersion in various concentrations of CaCl2 and MgCl2 aqueous solutions, respectively. The pasting properties, i.e., peak viscosity and breakdown, of all the starches obtained above were analyzed using a Rapid Visco Analyzer. Furthermore, the gelatinization properties and in vitro digestibility of the representative calcium- and magnesium-fortified starches were tested. The maximum calcium content of the fortified potato starches was as high as 686 ppm with the addition of a high-concentration CaCl2 solution, while the calcium content of the control potato starch was 99 ppm. The magnesium content increased from 89 to 421 ppm by treatment of the potato starch with an MgCl2 solution. Markedly lower values of peak viscosity and breakdown were observed in calcium- and magnesium-fortified potato starches than in the control potato starch. However, the gelatinization temperature and enthalpy as well as resistant starch content of calcium- and magnesium-fortified potato starches were similar to those of the control potato starch. It is concluded that potato starches with altered pasting properties can be easily manufactured by the use of solutions containing high levels of calcium and magnesium.

Effect of calcium hydroxide on mechanical strength and biological properties of bioactive glass.

PubMed

Shah, Asma Tufail; Batool, Madeeha; Chaudhry, Aqif Anwar; Iqbal, Farasat; Javaid, Ayesha; Zahid, Saba; Ilyas, Kanwal; Bin Qasim, Saad; Khan, Ather Farooq; Khan, Abdul Samad; Ur Rehman, Ihtesham

2016-08-01

In this manuscript for the first time calcium hydroxide (Ca(OH)2) has been used for preparation of bioactive glass (BG-2) by co-precipitation method and compared with glass prepared using calcium nitrate tetrahydrate Ca(NO3)2·4H2O (BG-1), which is a conventional source of calcium. The new source positively affected physical, biological and mechanical properties of BG-2. The glasses were characterized by Fourier transform infrared (FTIR), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA-DSC), BET surface area analysis and Knoop hardness. The results showed that BG-2 possessed relatively larger surface properties (100m(2)g(-1) surface area) as compared to BG-1 (78m(2)g(-1)), spherical morphology and crystalline phases (wollastonite and apatite) after sintering at lower than conventional temperature. These properties contribute critical role in both mechanical and biological properties of glasses. The Knoop hardness measurements revealed that BG-2 possessed much better hardness (0.43±0.06GPa at 680°C and 2.16±0.46GPa at 980°C) than BG-1 (0.24±0.01 at 680°C and 0.57±0.07GPA at 980°C) under same conditions. Alamar blue Assay and confocal microscopy revealed that BG-2 exhibited better attachment and proliferation of MG63 cells. Based on the improved biological properties of BG-2 as a consequent of novel calcium source selection, BG-2 is proposed as a bioactive ceramic for hard tissue repair and regeneration applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of peracetic acid on removing calcium hydroxide from the root canals.

PubMed

Sağsen, Burak; Ustün, Yakup; Aslan, Tuğrul; Canakçi, Burhan Can

2012-09-01

The goal of this study was to evaluate the efficiencies of different irrigation solutions in the removal of calcium hydroxide (CH). Forty-eight maxillary central incisor teeth were used. Root canals were prepared with the ProTaper system (Dentsply Maillefer, Baillagues, Switzerland). Five milliliters 2% NaOCl, 5 mL 17% EDTA, and 10 mL saline were used for final irrigation. The canals were filled with CH paste. Specimens were randomly divided into 4 experimental groups (n = 10) according to irrigation protocols. Positive and negative control groups (n = 4) were used. Group 1 used 2.5 mL 17% EDTA, group 2 used 2.5 mL 2.5% NaOCl + 2.5 mL 17% EDTA, group 3 used 2.5 mL 1% peracetic acid (PAA), and group 4 used 2.5 mL 0.5% PAA. The specimens were evaluated with scanning electron microscope analysis and scored. Kruskal-Wallis and Student Newman-Keuls post hoc tests were used for statistical analysis. In the apical thirds, 1% PAA was superior to the other groups (P < .05); however, there were no significant differences among the other groups (P > .05). In the middle thirds, no significant differences were found among the groups (P > .05). In the coronal thirds, 1% PAA was superior to the other groups. There were significant differences among all the other groups (P < .05). According to the findings of the present study, 1% PAA could be recommended for the removal of CH from the root canals. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

Efficacy of Erbium, Chromium-doped:Yttrium, Scandium, Gallium, and Garnet Laser Irradiation Combined with Resin-based Tricalcium Silicate and Calcium Hydroxide on Direct Pulp Capping: A Randomized Clinical Trial.

PubMed

Cengiz, Esra; Yilmaz, Hasan Guney

2016-03-01

The purpose of this randomized clinical study was to evaluate the efficiency of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation combined with a resin-based tricalcium silicate material and calcium hydroxide in direct pulp capping for a 6-month follow-up period. A total of 60 teeth of 60 patients between the ages of 18 and 41 years were recruited for this study. Sixty permanent vital teeth without symptoms and radiographic changes were randomly assigned to the following 4 groups (n = 15): Gr CH, the exposed area was sealed with calcium hydroxide (CH) paste; Gr laser CH, the treated area was sealed with CH paste after Er,Cr:YSGG laser irradiation at an energy level of 0.5 W without water and with 45% air; Gr TheraCal, TheraCal LC (Bisco, Schaumburg, IL) was applied directly to the exposed pulp; and Gr Laser TheraCal, TheraCal LC was applied after irradiation with an Er,Cr:YSGG laser. At the 1-week and 1-, 3-, and 6-month recall examinations, the loss of vitality, spontaneous pain, reactions to thermal stimuli and percussion, and radiographic changes were considered as failure. The success rates in the CH and TheraCal groups were 73.3% and 66.6%, respectively. These rates did not reveal any significant difference. In both laser groups, success rates were 100%. The Er,Cr:YSGG laser-irradiated TheraCal and Er,Cr:YSGG laser-irradiated CH groups showed statistically higher success rates than the TheraCal and CH groups, respectively. Er,Cr:YSGG laser irradiation at 0.5 W without water combined with pulp capping agents can be recommended for direct pulp therapy. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A Comparative Analysis of Antimicrobial Property of Wine and Ozone with Calcium Hydroxide and Chlorhexidine

PubMed Central

Ebenezar, A. V. Rajesh; Anand, Nirupa; Mary, A.Vinita; Mony, Bejoy

2015-01-01

Background The antibacterial properties of wine and ozone have been established but their antibacterial efficacies against endodontic pathogens are yet to be ascertained. Aim The purpose of this study is to comparatively evaluate the antibacterial property of ozonated water, white wine (14%) and de-alcoholised white wine. Materials and Methods S.mutans and E.faecalis were subcultured and inoculated in a nutrient broth for 24 hours. The following groups were formulated: Group 1A:2% Chlorhexidine (Control group); Group 1B:White wine; Group 1C:Dealcoholised white wine; Group 1D:Ozonated water; Group 2A: Ca(OH)2 + Chlorhexidine (Control group); Group 2B: White wine + Ca(OH)2; Group 2C:De-alcoholised White wine + Ca(OH)2 + chlorhexidine; Group 2D:White wine + Ca(OH)2 + chlorhexidine and group 2E: Dealcoholised white wine + Ca(OH)2 + chlorhexidine. The samples were allowed to diffuse into the culture medium for two hours, later the S. mutans were streaked on to the blood agar medium and the E. faecalis were streaked on to the Muller Hilton agar medium and incubated for 48 hours at 370C the zone of inhibition was measured after 48 hours. Results There was no growth of microorganisms seen with ozonated water. Chlorhexidine showed large zone of inhibition compared to the other groups. White wine has better antimicrobial property than de-alcoholised white wine, but when mixed with calcium hydroxide the dealcoholised white wine has better action against the microorganisms. Conclusion Ozonated water has the best antibacterial property and the antibacterial action of Calcium hydroxide is enhanced when it is mixed with de-alcoholised white wine. PMID:26266206

Biocompatibility of root filling pastes used in primary teeth.

PubMed

Lima, C C B; Conde Júnior, A M; Rizzo, M S; Moura, R D; Moura, M S; Lima, M D M; Moura, L F A D

2015-05-01

To evaluate the biocompatibility of two pastes designed to fill the root canals of primary teeth. A study group of 54 mice received subcutaneous tissue implants of polyethylene tubes containing CTZ or calcium hydroxide paste or, as a negative control, empty tubes. Biocompatibility was evaluated on days 7, 21 and 63, yielding a total of nine groups of six animals each. Following the experimental intervals, the implant areas were removed and subjected to histologic processing. After the tissues were stained with HE and Masson trichrome, two pathologists performed a histologic analysis of the samples in a blinded manner. Collagen fibre formation, tissue thickness and inflammatory cell infiltration were analysed qualitatively. Quantitative morphometry was performed for the thickness, perimeter length and tissue area of the region in direct contact with the open tube. anova with the Tukey post-test and Kruskal-Wallis analysis followed by Dunn's post-test, with significance established as P < 0.05, were used for data analysis. At 7 days, all groups had severe acute inflammatory infiltrates. Inflammation was reduced at 21 days in the CTZ paste group. Mild chronic inflammatory infiltrates were observed after 63 days in the CTZ and Ca(OH)2 paste groups; these groups also showed a significant decrease in collagen fibre density (P < 0.05), which was not observed in the control group. The average tissue thickness, perimeter length and area in contact with the tube decreased during the experimental periods in all groups. The CTZ and calcium hydroxide pastes demonstrated biocompatibility with subcutaneous tissue in this experimental model. © 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.

Tissue reaction to a triantibiotic paste used for endodontic tissue self-regeneration of nonvital immature permanent teeth.

PubMed

Gomes-Filho, João Eduardo; Duarte, Paulo Carvalho Tobias; de Oliveira, Claudiel Batista; Watanabe, Simone; Lodi, Carolina Simonetti; Cintra, Luciano Tavares Ângelo; Bernabé, Pedro Felício Estrada

2012-01-01

The endodontic regenerative procedure (ERP), which is an alternative to calcium hydroxide-induced apexification, involves the use of a triple antibiotic paste (TAP) as a dressing material. The aim of this study was to evaluate the response of rat subcutaneous tissue to implanted polyethylene tubes that were filled with TAP or calcium hydroxide. Thirty rats received 2 individual implants of polyethylene tubes filled with TAP or calcium hydroxide paste (CHP) and another empty tube as a control. Thirty additional rats received 2 individual implants consisting of polyethylene tubes filled with dressing material carriers (macrogol and propylene glycol) and a sham procedure. After 7, 15, 30, 60, and 90 days, 12 animals were euthanized, and the tubes and surrounding tissue were removed and processed for histology by using glycol methacrylate and stained with hematoxylin and eosin. The histological score ranged from 0 to 3 depending on the content of inflammatory cells; the fibrous capsule was considered thin or thick, and necrosis and calcification were recorded as present or absent. The results were analyzed using the Kruskal-Wallis test. Both dressing materials induced moderate reactions at 7 and 15 days. These reactions were similar to the control (P > .05) and reduced in intensity (to mild) from day 30 onward (P > .05). The carriers did not interfere with the reaction of the dressing materials. TAP and CHP were biocompatible over the different experimental periods examined. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide.

PubMed

Nosrat, Ali; Peimani, Ali; Asgary, Saeed

2013-11-01

The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement. A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation. All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples. This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable.

Mineral trioxide aggregate versus calcium hydroxide for pulpotomy in primary molars.

PubMed

Liu, He; Zhou, Qiong; Qin, Man

2011-01-01

To compare the effects of mineral trioxide aggregate (MTA) and calcium hydroxide (CH) for pulpotomy in primary molars. A randomised, bilateral self-controlled clinical trial was designed to compare the clinical effect of MTA and CH in pulpotomies in primary molars in 4- to 9-year-old children. Children with two similar-sized cavities on bilateral primary molar counterparts requiring pulpotomies were included. The two contralateral molars in each patient were randomly assigned to MTA or CH treatment. Clinical and radiographic examinations were performed to evaluate the treatment results at post-treatment recall. Seventeen pairs of self-controlled contralateral teeth were available for follow-up evaluations. The success rate of MTA was 94.1% (16/17), while the success rate of CH was 64.7% (11/17). Internal root resorption was the most frequent reason for failure in the CH group. Crown discolouration was common in the MTA-treated group. MTA was more successful than CH for pulpotomies in primary molar teeth, and may be a suitable replacement for CH in primary molar pulpotomies.

Comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain and aloe vera (all in gel formulation), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis: An in vitro study.

PubMed

Bhardwaj, Anuj; Ballal, Suma; Velmurugan, Natanasabapathy

2012-07-01

A comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain, and aloe vera (all in gel formulations), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis-an in vitro study. The antimicrobial efficacy was assessed in vitro using dentin shavings collected at 2 depths of 200 and 400 μm. The total colony forming units at the end of 1, 3, and 5 days were assessed. The overall percentage inhibition of bacterial growth (200 and 400 μm depth) was 100% with chlorhexidine gel. This was followed by M. citrifolia gel (86.02%), which showed better antimicrobial efficacy as compared with aloe vera gel (78.9%), papain gel (67.3%), and calcium hydroxide (64.3%). There was no statistical difference between data at 200 and 400 μm depth. Chlorhexidine gel showed the maximum antimicrobial activity against E. faecalis, whereas calcium hydroxide showed the least. Among the natural intracanal medicaments, M. citrifolia gel consistently exhibited good inhibition up to the 5(th) day followed by aloe vera gel and papain gel.

Comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain and aloe vera (all in gel formulation), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis: An in vitro study

PubMed Central

Bhardwaj, Anuj; Ballal, Suma; Velmurugan, Natanasabapathy

2012-01-01

Aim: A comparative evaluation of the antimicrobial activity of natural extracts of Morinda citrifolia, papain, and aloe vera (all in gel formulations), 2% chlorhexidine gel and calcium hydroxide, against Enterococcus faecalis—an in vitro study. Materials and Methods: The antimicrobial efficacy was assessed in vitro using dentin shavings collected at 2 depths of 200 and 400 μm. The total colony forming units at the end of 1, 3, and 5 days were assessed. Results: The overall percentage inhibition of bacterial growth (200 and 400 μm depth) was 100% with chlorhexidine gel. This was followed by M. citrifolia gel (86.02%), which showed better antimicrobial efficacy as compared with aloe vera gel (78.9%), papain gel (67.3%), and calcium hydroxide (64.3%). There was no statistical difference between data at 200 and 400 μm depth. Conclusion: Chlorhexidine gel showed the maximum antimicrobial activity against E. faecalis, whereas calcium hydroxide showed the least. Among the natural intracanal medicaments, M. citrifolia gel consistently exhibited good inhibition up to the 5th day followed by aloe vera gel and papain gel. PMID:22876022

The effects of calcium hydroxide-treated whole-plant and fractionated corn silage on intake, digestion, and lactation performance in dairy cows.

PubMed

Cook, D E; Bender, R W; Shinners, K J; Combs, D K

2016-07-01

The objective of this trial was to evaluate, in dairy cattle, the effects of calcium hydroxide treatment of whole-plant corn and a treatment applied to the bottom stalk fraction of the corn plant, achieved by harvesting corn in 2 crop streams. The treatments were calcium hydroxide-treated corn silage (TRTCS), toplage supplemented with calcium hydroxide-treated stalklage (TPL), a positive control of brown midrib corn silage (BMR), and a negative control of conventional whole-plant corn silage (WPCS). The toplage was harvested at a height of 82 cm with 2 of the 6 rows set as ear-snapping to incorporate higher tissues into the stalklage. Stalklage was harvested at 12 cm, and other corn silages were harvested at 27 cm. Sixteen pens, each with 8 Holstein cows averaging 70±25 d in milk and 46±11 kg of milk d(-1), were assigned 4 per treatment in a completely randomized design. The diet was approximately 40% corn silage, 20% alfalfa silage, and 40% concentrate on a dry matter basis. A 2-wk covariate period with conventional corn silage was followed by an 8-wk treatment period in which the 4 corn silage treatments were the only effective difference in diets. Cows fed TPL and TRTCS consumed more (1.9 and 1.4 kg of organic matter d(-1), respectively) than did cows fed WPCS. Milk yield was greater for cows fed BMR, TPL, and TRTCS. Cows fed BMR and TPL produced 2.9 and 2.7 kg d(-1), respectively, more energy-corrected milk (ECM) than cows fed WPCS, and cows fed TRTCS had the greatest ECM production (4.8 kg of ECM d(-1) greater than cows fed WPCS). No differences in body weight or body condition scored were observed. Milk fat concentration was similar among treatments and milk protein concentration was reduced for TRTCS. Starch and neutral detergent fiber digestibility were greater for cows fed TRTCS. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Early age hydration of calcium sulfoaluminate (synthetic ye'elimite, C{sub 4}A{sub 3}S{sup ¯}) in the presence of gypsum and varying amounts of calcium hydroxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hargis, Craig W.; Kirchheim, Ana Paula; Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu

Suspensions of synthetic ye'elimite (C{sub 4}A{sub 3}S{sup ¯}) in a saturated gypsum (CS{sup ¯}H{sub 2}) and calcium hydroxide (CH) solution were examined in-situ in a wet cell by soft X-ray transmission microscopy and ex-situ by scanning electron microscopy. The most voluminous hydration product observed was ettringite. Ettringite commonly displayed acicular, filiform, reticulated, and stellate crystal habits. Additionally, pastes with C{sub 4}A{sub 3}S{sup ¯}, 15% CS{sup ¯}H{sub 2}, and varying amounts of CH were prepared and examined with X-ray diffraction (XRD) and isothermal calorimetry. The XRD experiments showed that increasing CH content caused more solid solution (SO{sub 4}{sup 2−}/OH{sup −}) AFmmore » phases to form at early ages (< 1 d) and more monosulfate to form at later ages (> 1 d). Calorimetry indicated that the increased production of solid solution AFm was accompanied with an increase in the initial (< 30 min) rate of heat evolution, and increasing CH generally reduced the time till the second maximum rate of heat evolution due to the formation of ettringite and monosulfate.« less

21 CFR 184.1195 - Calcium citrate.

Code of Federal Regulations, 2012 CFR

2012-04-01

..., CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and...

21 CFR 184.1195 - Calcium citrate.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or calcium carbonate. It occurs as a fine white, odorless powder and...

A preliminary report on histological outcome of pulpotomy with endodontic biomaterials vs calcium hydroxide

PubMed Central

Peimani, Ali; Asgary, Saeed

2013-01-01

Objectives The purpose of the study was to evaluate human dental pulp response to pulpotomy with calcium hydroxide (CH), mineral trioxide aggregate (MTA), and calcium enriched mixture (CEM) cement. Materials and Methods A total of nine erupted third molars were randomly assigned to each pulpotomy group. The same clinician performed full pulpotomies and coronal restorations. The patients were followed clinically for six months; the teeth were then extracted and prepared for histological assessments. The samples were blindly assessed by an independent observer for pulp vitality, pulp inflammation, and calcified bridge formation. Results All patients were free of clinical signs/symptoms of pulpal/periradicular diseases during the follow up period. In CH group, one tooth had necrotic radicular pulp; other two teeth in this group had vital uninflamed pulps with complete dentinal bridge formation. In CEM cement and MTA groups all teeth had vital uninflamed radicular pulps. A complete dentinal bridge was formed beneath CEM cement and MTA in all roots. Odontoblast-like cells were present beneath CEM cement and MTA in all samples. Conclusions This study revealed that CEM cement and MTA were reliable endodontic biomaterials in full pulpotomy treatment. In contrast, the human dental pulp response to CH might be unpredictable. PMID:24303358

The effect of sodium hypochlorite application on the success of calcium hydroxide and mineral trioxide aggregate pulpotomies in primary teeth.

PubMed

Akcay, Merve; Sari, Saziye

2014-01-01

This study's purpose was to evaluate the success of calcium hydroxide (CH) and mineral trioxide aggregate (MTA) pulpotomies following the use of five percent sodium hypochlorite (NaOCl) as an antibacterial agent to clean the chamber prior to application of the pulpotomy agent. A total of 128 teeth were randomly divided into two pulpotomy groups (CH or MTA). The teeth in each pulpotomy group, CH and MTA, were further randomly divided into subgroups to receive either the NaOCl (experimental) or saline (control) cleaning agent prior to applying the pulpotomy agent. The treatments were followed clinically and radiographically for 12 months. The radiographic success rates were 84 percent for CH NaOCl, 74 percent for CH saline control, 97 percent for MTA NaOCl, and 100 percent for MTA saline control. There were no significant differences between the radiographic success rates in the CH and MTA subgroups (CH NaOCl-CH control and MTA NaOCl-MTA control); no significant differences were observed when comparing the CH NaOCl-MTA NaOCl groups and the CH NaOCl-MTA control groups. Use of sodium hypochlorite as an antibacterial agent prior to application of the pulpotomy agent improved the success of calcium hydroxide pulpotomies to equal the success of mineral trioxide aggregate pulpotomies for observation up to 12 months.

21 CFR 184.1191 - Calcium carbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium carbonate. 184.1191 Section 184.1191 Food... GRAS § 184.1191 Calcium carbonate. (a) Calcium carbonate (CaCO3, CAS Reg. No. 471-34-1) is prepared by... of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of...

Comparison of the adjuvant activity of aluminum hydroxide and calcium phosphate on the antibody response towards Bothrops asper snake venom.

PubMed

Olmedo, Hidekel; Herrera, María; Rojas, Leonardo; Villalta, Mauren; Vargas, Mariángela; Leiguez, Elbio; Teixeira, Catarina; Estrada, Ricardo; Gutiérrez, José María; León, Guillermo; Montero, Mavis L

2014-01-01

The adjuvanticity of aluminum hydroxide and calcium phosphate on the antibody response in mice towards the venom of the snake Bothrops asper was studied. It was found that, in vitro, most of the venom proteins are similarly adsorbed by both mineral salts, with the exception of some basic phospholipases A2, which are better adsorbed by calcium phosphate. After injection, the adjuvants promoted a slow release of the venom, as judged by the lack of acute toxicity when lethal doses of venom were administered to mice. Leukocyte recruitment induced by the venom was enhanced when it was adsorbed on both mineral salts; however, venom adsorbed on calcium phosphate induced a higher antibody response towards all tested HPLC fractions of the venom. On the other hand, co-precipitation of venom with calcium phosphate was the best strategy for increasing: (1) the capacity of the salt to couple venom proteins in vitro; (2) the venom ability to induce leukocyte recruitment; (3) phagocytosis by macrophages; and (4) a host antibody response. These findings suggest that the chemical nature is not the only one determining factor of the adjuvant activity of mineral salts.

21 CFR 184.1207 - Calcium lactate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

21 CFR 184.1207 - Calcium lactate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

21 CFR 184.1207 - Calcium lactate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... lactic acid with calcium carbonate or calcium hydroxide. (b) The ingredient meets the specifications of... manufacturing practice. (d) Prior sanctions for this ingredient different from the uses established in this...

Reactivity of NO2 and CO2 with hardened cement paste containing activated carbon

NASA Astrophysics Data System (ADS)

Horgnies, M.; Dubois-Brugger, I.; Krou, N. J.; Batonneau-Gener, I.; Belin, T.; Mignard, S.

2015-07-01

The development of building materials to reduce the concentration of NO2 is growing interest in a world where the air quality in urban areas is affected by the car traffic. The main binder in concrete is the cement paste that is partly composed of calcium hydroxide. This alkaline hydrate composing the hardened cement paste shows a high BET surface area (close to 100 m2.g-1) and can absorb low-concentrations of NO2. However, the presence of CO2 in the atmosphere limits the de-polluting effect of reference cement paste, mainly due to carbonation of the alkaline hydrates (reaction leading to the formation of calcium carbonate). The results established in this paper demonstrate that the addition of activated carbon in the cement paste, because of its very high BET surface area (close to 800 m2.g-1) and its specific reactivity with NO2, can significantly improve and prolong the de-polluting effect in presence of CO2 and even after complete carbonation of the surface of the cement paste.

[Calcium carbonate for the treatment of hyperphosphatemia in chronic hemodialysis patients].

PubMed

Kiss, D; Battegay, M; Meier, C; Lyrer, A

1990-03-03

Hyperphosphatemia in chronic hemodialysis patients is usually treated with aluminium containing phosphate binders. In recent years there has been increasing evidence of serious complications due to aluminium accumulation. We have investigated a new calcium carbonate preparation with an HCl-resistant capsule designed to prevent gastrointestinal side effects. Its phosphate binding capacity in comparison to aluminium chloride hydroxide was investigated in 17 chronic hemodialysis patients. The dose of the phosphate binder was adjusted regularly so that the serum phosphorus levels were below 1.8 mmol/l. The mean dose of aluminium chloride hydroxide was 3.36 g/day and of calcium carbonate 4.96 g/day. The mean (+/- SD) serum calcium level was 2.58 +/- 0.11 mmol/l under aluminium chloride hydroxide and 2.50 +/- 0.25 mmol/l under calcium carbonate. The mean phosphorus level was 1.69 +/- 0.31 mmol/l under aluminium chloride hydroxide and 1.71 +/- 0.33 under calcium carbonate. Serum aluminium fell from 64.5 +/- 14.4 micrograms/l to 28.5 +/- 17.5 micrograms/l after 3 months.

21 CFR 184.1195 - Calcium citrate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... GRAS § 184.1195 Calcium citrate. (a) Calcium citrate (Ca3(C6H5O7)2·4H2O, CAS Reg. No. 813-0994-095) is the calcium salt of citric acid. It is prepared by neutralizing citric acid with calcium hydroxide or...

Electrochemical cell with calcium anode

DOEpatents

Cooper, John F.; Hosmer, Pamela K.; Kelly, Benjamin E.

1979-01-01

An electrochemical cell comprising a calcium anode and a suitable cathode in an alkaline electrolyte consisting essentially of an aqueous solution of an hydroxide and a chloride. Specifically disclosed is a mechanically rechargeable calcium/air fuel cell with an aqueous NaOH/NaCl electrolyte.

[Efficacy of sodium hydroxide at 2.5 %, chlorhexidine gluconate at 0.5 % and calcium hydroxide against Candida albicans].

PubMed

Ndiaye, D; Diongue, K; Bane, K; Seck, A; Niang, S O; Lèye Benoist, F; Ndiaye, D; Touré, B

2016-12-01

Endodontic flora is dominated in the apical part of the channels by strict anaerobic and some facultative anaerobic bacteria but also by Candida yeasts, especially Candida albicans species that are involved in the maintenance and persistence of endodontic infections. Their elimination of the canal system in practice by chemo-mechanical methods of disinfection is not always guaranteed. Thus, this in vitro study was performed to determine the sensitivity of C. albicans with sodium hypochlorite (NaOCl) dosed at 2.5 %, the chlorhexidine digluconate 0.5 % and calcium hydroxide used in inter-session medication. The diffusion method was used initially to test the sensitivity of C. albicans strains with the above products. Then a dilution technique has allowed us to determine the minimum inhibitory concentration of these active products on C. albicans. Strains from infected pulp teeth of patients showed a sensitivity of C. albicans to sodium hypochlorite to a minimum inhibitory concentration less than 70μg/mL and 30μg/mL for chlorhexidine. This study demonstrated a sensitivity of C. albicans to sodium hypochlorite and chlorhexidine. Copyright © 2016. Published by Elsevier Masson SAS.

Comparative efficacy of photo-activated disinfection and calcium hydroxide for disinfection of remaining carious dentin in deep cavities: a clinical study

PubMed Central

Sharma, Sidhartha; Shah, Naseem

2014-01-01

Objectives To comparatively evaluate the efficacy of photo-activated disinfection (PAD), calcium hydroxide (CH) and their combination on the treatment outcome of indirect pulp treatment (IPT). Materials and Methods Institutional ethical clearance and informed consent of the patients were taken. The study was also registered with clinical registry of India. Sixty permanent molars exhibiting deep occlusal carious lesion in patients with the age range of 18 - 22 yr were included. Clinical and radiographic evaluation and set inclusion and exclusion criteria's were followed. Gross caries excavation was accomplished. In group I (n = 20) PAD was applied for sixty seconds. In group II (n = 20), CH was applied to the remaining carious dentin, while in group III (n = 20), PAD application was followed by CH placement. The teeth were permanently restored. They were clinically and radiographically followed-up at 45 day, 6 mon and 12 mon. Relative density of the remaining affected dentin was measured by 'Radiovisiography (RVG) densitometric' analysis. Results Successful outcome with an increase in radiographic grey values were observed in all three groups. However, on inter-group comparison, this change was not significant (p > 0.05). Conclusions PAD and CH both have equal disinfection efficacy in the treatment of deep carious dentin. PAD alone is as effective for treatment of deep carious lesion as calcium hydroxide and hence can be used as an alternative to CH. They can be used independently in IPT, since combining both does not offer any additional therapeutic benefits. PMID:25110643

A titration model for evaluating calcium hydroxide removal techniques.

PubMed

Phillips, Mark; McClanahan, Scott; Bowles, Walter

2015-01-01

Calcium hydroxide (Ca(OH)2) has been used in endodontics as an intracanal medicament due to its antimicrobial effects and its ability to inactivate bacterial endotoxin. The inability to totally remove this intracanal medicament from the root canal system, however, may interfere with the setting of eugenol-based sealers or inhibit bonding of resin to dentin, thus presenting clinical challenges with endodontic treatment. This study used a chemical titration method to measure residual Ca(OH)2 left after different endodontic irrigation methods. Eighty-six human canine roots were prepared for obturation. Thirty teeth were filled with known but different amounts of Ca(OH)2 for 7 days, which were dissolved out and titrated to quantitate the residual Ca(OH)2 recovered from each root to produce a standard curve. Forty-eight of the remaining teeth were filled with equal amounts of Ca(OH)2 followed by gross Ca(OH)2 removal using hand files and randomized treatment of either: 1) Syringe irrigation; 2) Syringe irrigation with use of an apical file; 3) Syringe irrigation with added 30 s of passive ultrasonic irrigation (PUI), or 4) Syringe irrigation with apical file and PUI (n=12/group). Residual Ca(OH)2 was dissolved with glycerin and titrated to measure residual Ca(OH)2 left in the root. No method completely removed all residual Ca(OH)2. The addition of 30 s PUI with or without apical file use removed Ca(OH)2 significantly better than irrigation alone. This technique allowed quantification of residual Ca(OH)2. The use of PUI (with or without apical file) resulted in significantly lower Ca(OH)2 residue compared to irrigation alone.

Preparation of hydroxyapatite/collagen injectable bone paste with an anti-washout property utilizing sodium alginate. Part 1: influences of excess supplementation of calcium compounds.

PubMed

Sato, Taira; Kikuchi, Masanori; Aizawa, Mamoru

2017-03-01

The anti-washout property, viscosity, and cytocompatibility to an osteoblastic cell line, MG-63, of anti-washout pastes were investigated. Mixing a hydroxyapatite/collagen bone-like nanocomposite (HAp/Col), an aqueous solution of sodium alginate (Na-Alg), which is a paste hardening and lubricant agent, and supplementation of calcium carbonate or calcium citrate (Ca-Cit) as a calcium resource for the hardening reaction realized an injectable bone paste. Adding Ca-Cit at a concentration greater than eight times the Ca 2+ ion concentration to Na-Alg improved the anti-washout property. Although the viscosity test indicated a gradual increase in the paste viscosity as the calcium compounds increased, pastes with excess supplementation of calcium compounds exhibited injectability through a syringe with a 1.8 mm inner diameter, realizing an injectable bone filler. Furthermore, the anti-washout pastes with Ca-Cit had almost the same cell proliferation rate as that of the HAp/Col dense body. Therefore, HAp/Col injectable anti-washout pastes composed of the HAp/Col, Na-Alg, and Ca-Cit are potential candidates for bioresorbable bone filler pastes.

Micro-computed tomography evaluation of the removal of calcium hydroxide medicament from C-shaped root canals of mandibular second molars.

PubMed

Ma, J Z; Shen, Y; Al-Ashaw, A J; Khaleel, H Y; Yang, Y; Wang, Z J; Peng, B; Haapasalo, M

2015-04-01

To use micro-computed tomography (μ-CT) to evaluate the amount of calcium hydroxide [Ca(OH)2 ] remaining in the C-shaped root canals of mandibular second molars after attempting to remove it with passive ultrasonic and sonic irrigation. Thirty mandibular second molars, 15 in C1 and 15 in C2 configurations as first identified by μ-CT, were divided into three groups (five C1 and five C2 in each group) for the three irrigation methods. All teeth were prepared to ProTaper Universal F2 and filled with Ca(OH)2 paste. The Ca(OH)2 was removed with F2 files and irrigation without agitation or with agitation using either EndoActivator or ultrasonics. μ-CT was used to measure the initial amount of Ca(OH)2 present. After removal of Ca(OH)2, μ-CT imaging was used to assess the percentage of volume of residual Ca(OH)2 in the canal. Data were analysed using one-way anova test. There was no significant difference in the mean volume of the root canal systems after instrumentation amongst the three groups. The three irrigation techniques left 2-17% of Ca(OH)2 in the root canals after removal. The mean volume of the remaining Ca(OH)2 was higher in the group without agitation than in the groups with sonic or ultrasonic agitation (P < 0.05). In the apical third, 68% of the canal space remained occupied by Ca(OH)2 when no agitation was used, whereas 28% and 31% remained filled by Ca(OH)2 in the EndoActivator and ultrasonic groups, respectively. There was no significant difference in the amount of residual Ca(OH)2 between the EndoActivator and ultrasonic groups. The proportion of remaining Ca(OH)2 in the apical canals was higher than in the middle and coronal canals in all groups (P < 0.05). A considerable proportion of the apical canal space remained filled with Ca(OH)2 in the C-shaped root canals after instrumentation and conventional needle irrigation. Although combining rotary instrumentation and irrigation with sonic or ultrasonic agitation reduced the amount of residual Ca

On the structure of amorphous calcium carbonate--a detailed study by solid-state NMR spectroscopy.

PubMed

Nebel, Holger; Neumann, Markus; Mayer, Christian; Epple, Matthias

2008-09-01

The calcium carbonate phases calcite, aragonite, vaterite, monohydrocalcite (calcium carbonate monohydrate), and ikaite (calcium carbonate hexahydrate) were studied by solid-state NMR spectroscopy ( (1)H and (13)C). Further model compounds were sodium hydrogencarbonate, potassium hydrogencarbonate, and calcium hydroxide. With the help of these data, the structure of synthetically prepared additive-free amorphous calcium carbonate (ACC) was analyzed. ACC contains molecular water (as H 2O), a small amount of mobile hydroxide, and no hydrogencarbonate. This supports the concept of ACC as a transient precursor in the formation of calcium carbonate biominerals.

21 CFR 184.1205 - Calcium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

.... No. 1305-62-0) is also known as slaked lime or calcium hydrate. It is produced by the hydration of lime. (b) The ingredient meets the specifications of the Food Chemicals Codex, 3d Ed. (1981), p. 52...

Antimicrobial efficacy of octenidine hydrochloride, MTAD and chlorhexidine gluconate mixed with calcium hydroxide.

PubMed

Tirali, Resmiye Ebru; Gulsahi, Kamran; Cehreli, Sevi Burcak; Karahan, Zeynep Ceren; Uzunoğlu, Emel; Elhan, Atilla

2013-05-01

The aim of this in vitro study was to investigate whether mixing with calcium hydroxide [Ca(OH)2] affects the antimicrobial action of Octenidine hydrochloride (Octenisept), MTAD and chlorhexidine against Enterococcus faecalis and Candida albicans. Freshly grown cultures of Enterococcus faecalis, Candida albicans and a mixture of both strains were incubated in agar plates containing brain-heart infusion broth (BHIB). Zones of inhibition were measured at 24 and 48 hours. Statistical analysis was performed using Mann-Whitney U test and Kruskal-Wallis one-way analysis of variance (ANOVA, both p=0.05). Mixing with Ca(OH)2 significantly increased the antibacterial effect of Octenisept (p<0.05), but did not alter its antifungal activity. Only chlorhexidine showed more antibacterial and antifungal efficiency compared to its Ca(OH)2-mixed version (both p<0.05). Mixing with Ca(OH)2 decreased the antibacterial efficacy of MTAD, but increased its antifungal effect (both p<0.05). These results demonstrate the differential effects of Ca(OH)2 addition on the antimicrobial action of the tested endodontic medicaments in vitro. Ca(OH)2 was as effective as its combination with all of the tested medicaments.

Alkali Silica Reaction In The Presence Of Metakaolin - The Significant Role of Calcium Hydroxide

NASA Astrophysics Data System (ADS)

Zapała-Sławeta, Justyna

2017-10-01

Reducing the internal corrosion, which is the result of reactions between alkalis and reactive aggregates is especially important in ensuring durability properties of concrete. One of the methods of inhibiting the reaction is using some mineral additives which have pozzolanic properties. This paper presents the efficacy of high-reactivity metakaolin in reducing expansion due to alkali-silica reaction. It was demonstrated that metakaolin in the amount from 5% to 20% by mass of Portland cement reduce linear expansion of mortar bars with opal aggregate. Nevertheless, the safe expansion level in the specimens, classified as non-destructive to concrete, was recorded for the mortars prepared with 20% addition of metakaolin. Depletion of free calcium hydroxide content was considered as one of the most beneficial effects of metakaolin in controlling alkali silica reaction. Based on thermogravimetric analysis (TGA) performed on mortar bars with and without metakaolin the differences in portlandite content were determined. Microstructural observation of the specimens containing metakaolin indicated the presence of a reaction products but fewer in number than those forming in the mortars without mineral additives.

Aluminum Hydroxide and Magnesium Hydroxide

MedlinePlus

Aluminum Hydroxide, Magnesium Hydroxide are antacids used together to relieve heartburn, acid indigestion, and upset stomach. They ... They combine with stomach acid and neutralize it. Aluminum Hydroxide, Magnesium Hydroxide are available without a prescription. ...

The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

NASA Astrophysics Data System (ADS)

Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

2018-01-01

Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

An in vitro comparison of casein phosphopeptide-amorphous calcium phosphate paste, casein phosphopeptide-amorphous calcium phosphate paste with fluoride and casein phosphopeptide-amorphous calcium phosphate varnish on the inhibition of demineralization and promotion of remineralization of enamel.

PubMed

Thakkar, Prachi Jayesh; Badakar, Chandrashekhar M; Hugar, Shivayogi M; Hallikerimath, Seema; Patel, Punit M; Shah, Parin

2017-01-01

This study aims to determine and compare the extent of inhibition of demineralization and promotion of remineralization of permanent molar enamel with and without application of three remineralizing agents. Forty extracted permanent molars were randomly divided into two groups 1 and 2, longitudinally sectioned into four and divided into subgroups A, B, C, and D. The sections were coated with nail varnish leaving a window of 3 mm × 3 mm. All sections of Group 1 were treated with their respective subgroup-specific agent: Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste for subgroup A, CPP-amorphous calcium phosphate fluoride (ACPF) paste for subgroup B, CPP-ACPF varnish for subgroup C and subgroup D served as a control. The sections were then subjected to demineralization for 12 days following which lesional depth was measured under the stereomicroscope. All the sections of Group 2 were subjected to demineralization for 12 days, examined for lesional depth, then treated with their respective subgroup specific agents and immersed in artificial saliva for 7 days. The sections were then examined again under the stereomicroscope to measure the lesional depth. CPP-ACPF varnish caused significant inhibition of demineralization. All three agents showed significant remineralization of previously demineralized lesions. However, CPP-ACPF varnish showed the greatest remineralization, followed by CPP-ACPF paste and then CPP-ACP paste. This study shows that CPP-ACPF varnish is effective in preventing demineralization as well as promoting remineralization of enamel. Thus, it can be used as an effective preventive measure for pediatric patients where compliance with the use of tooth mousse may be questionable.

Evaluation of triple antibiotic paste removal by different irrigation procedures.

PubMed

Berkhoff, Julie A; Chen, Paul B; Teixeira, Fabricio B; Diogenes, Anibal

2014-08-01

Regenerative endodontics aims to re-establish a functional pulp-dentin complex. First, the root canal system is disinfected primarily by irrigants and medicaments. Triple antibiotic paste (TAP), a commonly used intracanal medicament, has been shown to be directly toxic to stem cells at concentrations greater than 0.1 g/mL. Thus, its complete removal is a crucial step in regenerative endodontic procedures. We hypothesized that currently used irrigation techniques do not completely remove TAP from root canal system. TAP was radiolabeled by the incorporation of I(125), and calcium hydroxide (Ultracal; Ultradent, South Jordan, UT) was radiolabeled with Ca(45). The intracanal medicaments were placed into standardized human root segments and incubated for 28 days at 37°C. Then, canals were irrigated with EndoActivator (Dentsply, Tulsa, OK), passive ultrasonic irrigation, EndoVac (SybronEndo, Coppell, TX), or a syringe/Max-i-Probe needle (Dentsply Rinn, Elgin, IL) using a standardized irrigation protocol in a closed system. Radioactivity levels (counts per minute values) were measured for each tooth before and after the irrigation protocols. Furthermore, the canals were sequentially enlarged and dentin samples collected and evaluated for radioactivity. Data were analyzed with analysis of variance and Bonferroni post hoc testing (P < .05). Approximately 88% of the TAP was retained in the root canal system regardless of the irrigation technique used (no difference among groups). Furthermore, approximately 50% of the radiolabeled TAP was present circumferentially up to 350 μm within the dentin. Conversely, up to 98% of the radiolabeled intracanal calcium hydroxide was removed, and most residual medicament was found present in the initial 50 μm of dentin. Current irrigation techniques do not effectively remove TAP from root canal systems, possibly because of its penetration and binding into dentin. However, calcium hydroxide is effectively removed with significant less

Histomicrobiologic aspects of the root canal system and periapical lesions in dogs' teeth after rotary instrumentation and intracanal dressing with Ca(OH)2 pastes.

PubMed

Soares, Janir Alves; Leonardo, Mário Roberto; da Silva, Léa Assed Bezerra; Tanomaru Filho, Mário; Ito, Izabel Yoko

2006-10-01

The purpose of this study was to evaluate the distribution of microorganisms in the root canal system (RCS) and periapical lesions of dogs' teeth after rotary instrumentation and placement of different calcium hydroxide [Ca(OH)2]-based intracanal dressings. Chronic periapical lesions were experimentally induced in 80 premolar roots of four dogs. Instrumentation was undertaken using the ProFile rotary system and irrigation with 5.25% sodium hypochlorite. The following Ca(OH)2-based pastes were applied for 21 days: group 1 - Calen (n=18); group 2 - Calen+CPMC (n=20); group 3 - Ca(OH)2 p.a. + anaesthetic solution (n=16) and group 4 - Ca(OH)2 p.a.+ 2% chlorhexidine digluconate (n=18). Eight root canals without endodontic treatment constituted the control group. Histological sections were obtained and stained with Brown & Brenn staining technique to evaluate the presence of microorganisms in the main root canal, ramifications of the apical delta and secondary canals, apical cementoplasts, dentinal tubules, areas of cemental resorption and periapical lesions. The results were analyzed statistically by the Mann-Whitney U test (p<0.05). The control group showed the highest prevalence of microorganisms in all sites evaluated. Gram-positive cocci, bacilli and filaments were the most frequent morphotypes. Similar microbial distribution patterns in the RCS and areas of cementum resorption were observed in all groups (p>0.05). The percentage of RCS sites containing microorganisms in groups 1, 2, 3, 4 and control were: 67.6%, 62.5%, 78.2%, 62.0% and 87.6%, respectively. In conclusion, the histomicrobiological analysis showed that the rotary instrumentation and the different calcium hydroxide pastes employed did not effectively eliminate the infection from the RCS and periapical lesions. However, several bacteria seen in the histological sections were probably dead or were inactivated by the biomechanical preparation and calcium hydroxide-based intracanal dressing.

Instant dentin hypersensitivity relief of a single topical application of an in-office desensitizing paste containing 8% arginine and calcium carbonate: a split-mouth, randomized-controlled study.

PubMed

Kapferer, Ines; Pflug, Claudia; Kisielewsky, Irene; Giesinger, Johannes; Beier, Ulrike S; Dumfahrt, Herbert

2013-01-01

The aim of this study was to evaluate the clinical efficacy of an in-office desensitizing paste containing 8% arginine and calcium carbonate relative to calcium carbonate alone in the reduction of dentin hypersensitivity in a randomized, double-blind, split-mouth clinical trial. Sixty teeth (30 subjects) with an air blast hypersensitivity score of 2 or 3 (Schiff Cold Air Sensitivity Scale) were randomly assigned to one of two treatment groups: (1) test paste containing 8% arginine and calcium carbonate (elmex sensitive professional desensitizing paste) and (2) control paste: paris white (calcium carbonate). Tactile and air blast dentin hypersensitivity examinations were performed at baseline, immediately after paste application and 4 and 12 weeks later. A statistically significant difference in air blast (p = 0.001) and tactile (p = 0.047) hypersensitivity reduction over time was observed between the two therapy modes. After 12-weeks, statistically significant differences were indicated between the test and control group with respect to baseline-adjusted mean tactile (41.94%; p = 0.038) and air blast hypersensitivity scores (46.5%; p = 0.017). The tested in-office desensitizing paste containing 8.0% arginine and calcium carbonate provides significantly greater hypersensitivity relief compared to calcium carbonate alone.

Periodontal and endodontic infectious/inflammatory profile in primary periodontal lesions with secondary endodontic involvement after a calcium hydroxide-based intracanal medication.

PubMed

Duque, Thais M; Prado, Maira; Herrera, Daniel R; Gomes, Brenda P F A

2018-03-23

The aim of the present study was to investigate the effects of a calcium hydroxide-based intracanal medication (ICM) on periodontal and endodontic infectious/inflammatory contents and on periodontal clinical parameters in teeth with primary periodontal lesion and secondary endodontic involvement. Ten patients with abnormal pulp test results and deep probing depth derived from primary periodontal disease with secondary endodontic involvement were included. Samples were collected from root canals (RC) and periodontal pockets (PP) in order to investigate the microbiological status, levels of endotoxin (LPS), cytokines, and matrix metalloproteinases (MMP), before and after ICM. PCR was used for microbiological assessment. The kinetic-chromogenic LAL assay was used for LPS quantification. Quantikine ELISA kits were used for measurement of IL-1 α, IL-1 β, TNF-α, PGE 2 , MMP-2, MMP-3, MMP-8, MMP-9, and MMP-13 levels. The statistical analyses were made using the Friedman and Wilcoxon tests (p < 0.05). T test was used to compare data on periodontal characteristics. ICM did not reduce the number of microorganisms in PP and RC, except for Fusobacterium nucleatum in RC. There was a significant reduction in LPS, MMPs, IL-1 β, and TNF-α levels in PP after ICM. In RC, LPS, MMP13, PGE 2 , and IL-1β levels remained unaltered (p > 0.05); however, the levels of the other MMPs and cytokines were reduced (p < 0.05). After 1 year of the root canal treatment, tooth mobility was significantly reduced (p ≤ 0.05). The use of a calcium hydroxide-based ICM showed positive effects for periodontal treatment prognosis, as it reduced LPS, cytokine, and MMP levels in periodontal pockets. Patients presenting deep probing depth and undergoing periodontal treatment for at least 6 months, with no positive response to periodontal therapy, might benefit with the endodontic treatment.

Action of Chlorhexidine, Zingiber officinale, and Calcium Hydroxide on Candida albicans, Enterococcus faecalis, Escherichia coli, and Endotoxin in the Root Canals.

PubMed

Valera, Marcia C; Oliveira, Sarah Ac; Maekawa, Lilian E; Cardoso, Flávia Gr; Chung, Adriana; Silva, Stephanie Fp; Carvalho, Cláudio At

2016-02-01

The purpose of this in vitro study was to evaluate the antimicrobial activity of 2% chlorhexidine gel (CHX) as auxiliary chemical substance and intracanal medications on Candida albicans, Enterococcus faecalis, Escherichia coli, and their endotoxins in the root canals. The study was conducted on 48 single-rooted human teeth divided into four groups (n = 12), according to intracanal medications used: (1) Calcium hydroxide + apyrogenic saline solution (Ca(OH)2 + SS), (2) 20% ginger glycolic extract (GEN), (3) calcium hydroxide + 20% ginger glycolic extract (Ca(OH)2 + GEN), (4) apyrogenic SS (control). Collections were made from the root canal content before preparation (baseline-S1), immediately after instrumentation (S2), 7 days after instrumentation (S3), after 14 days the action of intracanal medication (S4), and 7 days after removal of the intracanal medication (S5). The antimicrobial activity and endotoxin content were analyzed for all collections. The results were statistically analyzed by the Kruskal-Wallis and Dunn tests at a significance level of 5%. After instrumentation with CHX, there was complete elimination of E. coli and C. albicans, except for E. faecalis, which was significantly reduced and then completely eliminated after intracanal medication. There was significant reduction of endotoxin after instrumentation. Comparison of collection after instrumentation and intracanal medication revealed reduction of endotoxins in all groups; this reduction was greater in group Ca(OH)2 followed by the group GEN. It was concluded that the instrumentation using CHX and intracanal medication used were able to eliminate the microorganisms from the root canal; the endotoxins were reduced, yet not completely eliminated. This study is important and relevant for searching alternatives during endodontic therapy, since it aims to study the effect of Zingiber officinale on microorganisms and endotoxins present in root canals.

Effect of cetyl trimethyl ammonium bromide concentration on structure, morphology and carbon dioxide adsorption capacity of calcium hydroxide based sorbents

NASA Astrophysics Data System (ADS)

Hlaing, Nwe Ni; Vignesh, K.; Sreekantan, Srimala; Pung, Swee-Yong; Hinode, Hirofumi; Kurniawan, Winarto; Othman, Radzali; Thant, Aye Aye; Mohamed, Abdul Rahman; Salim, Chris

2016-02-01

Calcium hydroxide (Ca(OH)2) has been proposed as an important material for industrial, architectural, and environmental applications. In this study, calcium acetate was used as a precursor and cetyl trimethyl ammonium bromide (CTAB) was used as a surfactant to synthesize Ca(OH)2 based adsorbents for carbon dioxide (CO2) capture. The effect of CTAB concentration (0.2-0.8 M) on the structure, morphology and CO2 adsorption performance of Ca(OH)2 was studied in detail. The synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), BET surfaced area and thermogravimetry-differential thermal analysis (TG-DTA) techniques. The phase purity, crystallite size, Brunauer-Emmett-Teller (BET) surface area and CO2 adsorption performance of Ca(OH)2 precursor adsorbents were significantly increased when the concentration of CTAB was increased. XRD results showed that pure Ca(OH)2 phase was obtained at the CTAB concentration of 0.8 M. TGA results exhibited that 0.8 M of CTAB-assisted Ca(OH)2 precursor adsorbent possessed a residual carbonation conversion of ∼56% after 10 cycles.

SEPARATION OF PLUTONIUM HYDROXIDE FROM BISMUTH HYDROXIDE

DOEpatents

Watt, G.W.

1958-08-19

An tmproved method is described for separating plutonium hydroxide from bismuth hydroxide. The end product of the bismuth phosphate processes for the separation amd concentration of plutonium is a inixture of bismuth hydroxide amd plutonium hydroxide. It has been found that these compounds can be advantageously separated by treatment with a reducing agent having a potential sufficient to reduce bismuth hydroxide to metalltc bisinuth but not sufficient to reduce the plutonium present. The resulting mixture of metallic bismuth and plutonium hydroxide can then be separated by treatment with a material which will dissolve plutonium hydroxide but not metallic bismuth. Sodiunn stannite is mentioned as a preferred reducing agent, and dilute nitric acid may be used as the separatory solvent.

Process for converting magnesium fluoride to calcium fluoride

DOEpatents

Kreuzmann, A.B.; Palmer, D.A.

1984-12-21

This invention is a process for the conversion of magnesium fluoride to calcium fluoride whereby magnesium fluoride is decomposed by heating in the presence of calcium carbonate, calcium oxide or calcium hydroxide. Magnesium fluoride is a by-product of the reduction of uranium tetrafluoride to form uranium metal and has no known commercial use, thus its production creates a significant storage problem. The advantage of this invention is that the quality of calcium fluoride produced is sufficient to be used in the industrial manufacture of anhydrous hydrogen fluoride, steel mill flux or ceramic applications.

A novel approach for stabilizing fresh urine by calcium hydroxide addition

PubMed Central

Randall, Dyllon G.; Krähenbühl, Manuel; Köpping, Isabell; Larsen, Tove A.; Udert, Kai M.

2016-01-01

In this study, we investigated the prevention of enzymatic urea hydrolysis in fresh urine by increasing the pH with calcium hydroxide (Ca(OH)2) powder. The amount of Ca(OH)2 dissolving in fresh urine depends significantly on the composition of the urine. The different urine compositions used in our simulations showed that between 4.3 and 5.8 g Ca(OH)2 dissolved in 1 L of urine at 25 °C. At this temperature, the pH at saturation is 12.5 and is far above the pH of 11, which we identified as the upper limit for enzymatic urea hydrolysis. However, temperature has a strong effect on the saturation pH, with higher values being achieved at lower temperatures. Based on our results, we recommend a dosage of 10 g Ca(OH)2 L−1 of fresh urine to ensure solid Ca(OH)2 always remains in the urine reactor which ensures sufficiently high pH values. Besides providing sufficient Ca(OH)2, the temperature has to be kept in a certain range to prevent chemical urea hydrolysis. At temperatures below 14 °C, the saturation pH is higher than 13, which favors chemical urea hydrolysis. We chose a precautionary upper temperature of 40 °C because the rate of chemical urea hydrolysis increases at higher temperatures but this should be confirmed with kinetic studies. By considering the boundaries for pH and temperature developed in this study, urine can be stabilized effectively with Ca(OH)2 thereby simplifying later treatment processes or making direct use easier. PMID:27055084

Enhancement of bactericidal effects of sodium hypochlorite in chiller water with food additive grade calcium hydroxide.

PubMed

Toyofuku, Chiharu; Alam, Md Shahin; Yamada, Masashi; Komura, Miyuki; Suzuki, Mayuko; Hakim, Hakimullah; Sangsriratanakul, Natthanan; Shoham, Dany; Takehara, Kazuaki

2017-06-16

An alkaline agent, namely food additive grade calcium hydroxide (FdCa(OH) 2 ) in solution at 0.17%, was evaluated for its bactericidal efficacies in chiller water with sodium hypochlorite (NaOCl) at a concentration of 200 ppm total residual chlorine. Without organic material presence, NaOCl could inactivate Salmonella Infantis and Escherichia coli within 5 sec, but in the presence of fetal bovine serum (FBS) at 0.5%, the bactericidal effects of NaOCl were diminished completely. FdCa(OH) 2 solution required 3 min to inactivate bacteria with or without 5% FBS. When NaOCl and FdCa(OH) 2 were mixed at the final concentration of 200 ppm and 0.17%, respectively, the mixed solution could inactivate bacteria at acceptable level (10 3 reduction of bacterial titer) within 30 sec in the presence of 0.5% FBS. The mixed solution also inhibited cross-contamination with S. Infantis or E. coli on chicken meats. It was confirmed and elucidated that FdCa(OH) 2 has a synergistic effect together with NaOCl for inactivating microorganisms.

Precursor preparation for Ca-Al layered double hydroxide to remove hexavalent chromium coexisting with calcium and magnesium chlorides

NASA Astrophysics Data System (ADS)

Zhong, Lihua; He, Xiaoman; Qu, Jun; Li, Xuewei; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong

2017-01-01

Al(OH)3 and Ca(OH)2 powders are co-ground to prepare a precursor which hydrates into a layered double hydroxide (LDH) phase by agitation in aqueous solution with target hexavalent chromium (Cr(VI)) at room temperature, to achieve an obvious improvement in removal efficiency of Cr(VI) through an easy incorporation into the structure. Although the prepared precursor transforms into LDH phases also when agitated in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist. The adsorption isotherm and kinetic studies show that the phenomena occurring on the Al-Ca precursor fit a pseudo-second-order kinetics with a Langmuir adsorption capacity of 59.45 mg/g. Besides, characterizations of the prepared precursor and the samples after adsorption are also performed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Transmission electron microscope (TEM) to understand the reason of the preferential incorporation of Cr(VI) to the coexisting chloride salts during the LDH phase formation. Ca-Al precursor (C3A) was agitated in a hexavalent chromium (Cr(VI)) solution to form Al-Ca-CrO4 LDH product. Ca-Al-CrO4 LDH phase occurred preferentially to Ca-Al-MCl2 LDH phases in the solutions of calcium and magnesium chlorides, it incorporates Cr(VI) preferentially to the chloride salts when they coexist.

Concentration of Calcium, Phosphate and Fluoride Ions in Microbial Plaque and Saliva after Using CPP-ACP Paste in 6-9 year-old Children

PubMed Central

HR, Poureslami; Ra, Hoseinifar; Re, Hoseinifar; H, Sharifi; P, Poureslami

2016-01-01

Statement of Problem: Dental caries is one of the most common chronic diseases in children. The balance between demineralization and remineralization of the decayed teeth depends on the calcium and phosphate content of the tooth surface. Therefore, if a product such as casein phospho peptides - amorphous calcium phosphate (CPP- ACP) which can significantly increase the availability of calcium and phosphate in the plaque and saliva should have an anti-caries protective effect. Objectives: The purpose of this study was to evaluate the concentration of calcium, phosphate and fluoride in the plaque and saliva of children before and after applying the CPP-ACP paste. Materials and Methods: A total of 25 children aged between 6-9 years were selected for this clinical trial study. At first, 1 ml of unstimulated saliva was collected and then 1 mg of the plaque sample was collected from the buccal surfaces of the two first primary molars on the upper jaw. In the next step, CPP-ACP paste (GC Corp, Japan) was applied on the tooth surfaces and then the plaque and saliva sampling was performed after 60 minutes. The amount of calcium ions was measured by Ion meter instrument (Metrohm Co, Swiss) and the amounts of phosphate and fluoride ions were measured by Ion Chromatography instrument (Metrohm Co, Swiss). Data were analyzed using paired t-test at a p < 0.05 level of significance. Results: There were statistically significant differences in the calcium and phosphate concentration of the saliva and plaque before and after applying the CPP-ACP paste. There were also statistically significant differences in the fluoride levels of the plaque before and after applying the CPP-ACP paste. However, there were no statistically significant differences in the fluoride levels of the saliva before and after applying the CPP-ACP paste. Conclusions: In this study, the use of the CPP-ACP paste significantly increased the fluoride levels of the plaque and the calcium and phosphate levels of both

The effects of different irrigation protocols on removing calcium hydroxide from the root canals.

PubMed

Üstün, Y; Aslan, T; Sagsen, B; Dincer, A N

2016-01-01

The aim of this study was to evaluate the efficiencies of different irrigation protocols and solutions in the removal of calcium hydroxide (Ca[OH]2). Sixty-eight maxillary incisors were used. Root canals were prepared and filled with Ca(OH)2. Two control (n = 4) and six experimental groups (n = 10) were adjusted: Group 1:1% peracetic acid (PAA) + master apical file (MAF); Group 2: 17% ethylenediaminetetraacetic acid (EDTA) + MAF; Group 3: 9% 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) + MAF; Group 4: 1% PAA + ultrasonic activation (UA); Group 5: 17% EDTA + UA; Group 6: 9% HEBP + UA. The cleanliness of root canal thirds were evaluated with scanning electron microscopy. Statistical analysis were performed (α = 0.05). At coronal thirds; PAA + UA was superior to EDTA + MAF, HEBP + MAF; and PAA + MAF was superior to EDTA + MAF, HEBP + MAF (P < 0.05). At middle thirds; PAA + MAF and PAA + UA were superior to EDTA + MAF and EDTA + UA; and, PAA + UA was superior to HEBP + MAF (P < 0.05). There were no significant differences among the rest of the experimental groups (P > 0.05). Complete removal of Ca(OH)2could not be achieved by none of the irrigants at all root thirds.

Incidence of postoperative pain after use of calcium hydroxide mixed with normal saline or 0.2% chlorhexidine digluconate as intracanal medicament in the treatment of apical periodontitis.

PubMed

Menakaya, Ifeoma Nkiruka; Oderinu, Olabisi Hajarat; Adegbulugbe, Ilemobade Cyril; Shaba, Olufemi Peter

2015-10-01

To compare the incidence of postoperative pain after the use of calcium hydroxide powder mixed with normal saline or 0.2% chlorhexidine digluconate as intracanal medicament. Fifty-five subjects aged 17-60 years with teeth diagnosed to have apical periodontitis. Two-visit conventional root canal treatment of seventy teeth. The teeth were divided by randomization (balloting) into two groups: control group and experimental group, each with thirty-five teeth treated with calcium hydroxide mixed with normal saline or with 0.2% chlorhexidine digluconate as intracanal medicament respectively. Incidence of postoperative pain was assessed using the universal pain assessment tool and whether or not analgesic was taken. Incidence of post-operative pain. Postoperative pain occurred only at 1-day and 1-week reviews. In the control group, the overall incidence of pain was the same at both review periods (5.7%), while the experimental group showed a slight decrease in incidence between 1-day (17.2%) and 1-week (11.4%) reviews. Incidence of flare-ups was more in the experimental group (11.4%) than in the control group (5.7%). No significant statistical differences between the two groups were observed (p > 0.05). The incidence of postoperative pain was lower in the normal saline treatment group, but the difference was not statistically significant.

Calcium and lanthanum solid base catalysts for transesterification

DOEpatents

Ng, K. Y. Simon; Yan, Shuli; Salley, Steven O.

2015-07-28

In one aspect, a heterogeneous catalyst comprises calcium hydroxide and lanthanum hydroxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In another aspect, a heterogeneous catalyst comprises a calcium compound and a lanthanum compound, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g, and a total basicity of about 13.6 mmol/g. In further another aspect, a heterogeneous catalyst comprises calcium oxide and lanthanum oxide, wherein the catalyst has a specific surface area of more than about 10 m.sup.2/g. In still another aspect, a process for preparing a catalyst comprises introducing a base precipitant, a neutral precipitant, and an acid precipitant to a solution comprising a first metal ion and a second metal ion to form a precipitate. The process further comprises calcining the precipitate to provide the catalyst.

The effects of lithium hydroxide solution on alkali silica reaction gels created with opal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Lyndon D.; Beaudoin, James J.; Grattan-Bellew, Patrick

The reaction of Nevada opal with calcium hydroxide, potassium hydroxide and lithium hydroxide solutions was investigated. In addition, opal was exposed to a combined solution of these three hydroxides. The progress of the three reactions was followed using X-ray diffraction (XRD), {sup 29}Si nuclear magnetic resonance (NMR) and scanning electron microscopy (SEM). The XRD results indicated the presence of a low-angle peak exclusive to the lithium-based reactions. The NMR results suggested a change in the silicate structure in the presence of lithium. These techniques indicated that the reaction of the alkali with the opal starting material is inhibited and perhapsmore » stopped in the presence of lithium hydroxide. SEM revealed that the morphology of the reaction products on the surface of the reacted opal grains is markedly different invariably. It was concluded that evidence to support the theory of a protective layer exists and that the nature of the layer varies with ion type.« less

Important role of calcium chloride in preventing carbon monoxide generation during desflurane degradation with alkali hydroxide-free carbon dioxide absorbents.

PubMed

Ando, Takahiro; Mori, Atsushi; Ito, Rie; Nishiwaki, Kimitoshi

2017-12-01

We investigated whether calcium chloride (CaCl 2 ), a supplementary additive in carbon dioxide (CO 2 ) absorbents, could affect carbon monoxide (CO) production caused by desflurane degradation, using a Japanese alkali-free CO 2 absorbent Yabashi Lime ® -f (YL-f), its CaCl 2 -free and 1% CaCl 2 -added derivatives, and other commercially available alkali-free absorbents with or without CaCl 2 . The reaction between 1 L of desflurane gas (3-10%) and 20 g of desiccated specimen was performed in an artificial closed-circuit anesthesia system for 3 min at 20 or 40 °C. The CO concentration was measured using a gas chromatograph equipped with a semiconductor sensor detector. The systems were validated by detecting dose-dependent CO production with an alkali hydroxide-containing CO 2 absorbent, Sodasorb ® . Compared with YL-f, the CaCl 2 -free derivative caused the production of significantly more CO, while the 1% CaCl 2 -added derivative caused the production of a comparable amount of CO. These phenomena were confirmed using commercially available absorbents AMSORB ® PLUS, an alkali-free absorbent with CaCl 2 , and LoFloSorb™, an alkali-free absorbent without CaCl 2 . These results suggest that CaCl 2 plays an important role in preventing CO generation caused by desflurane degradation with alkali hydroxide-free CO 2 absorbents like YL-f.

Atomic hydrogen in. gamma. -irradiated hydroxides of alkaline-earth elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spitsyn, V.I.; Yurik, T.K.; Barsova, L.I.

1982-04-01

Atomic hydrogen is an important intermediate product formed in the radiolysis of compounds containing X-H bonds. H atoms have been detected in irradiated matrices of H/sub 2/ and inert gases at 4/sup 0/K, in irradiated ice and frozen solutions of acids in irradiated salts and in other systems. Here results are presented from a study of the ESR spectra of H atoms generated in polycrystalline hydroxides of alkaline-earth elements that have been ..gamma..-irradiated at 77/sup 0/K, after preliminary treatment at various temperatures. For the first time stabilization of atomic hydrogen in ..gamma..-irradiated polycrystalline alkaline-earth element hydroxides has been detected. Dependingmore » on the degree of dehydroxylation, several types of hydrogen atoms may be stabilized in the hydroxides, these hydrogen atoms having different radiospectroscopic parameters. In the magnesium-calcium-strontium-barium hydroxide series, a regular decrease has been found in the hfi constants for H atoms with the cations in the immediate surroundings. A direct proportionality has been found between the parameters ..delta..A/A/sub 0/ and the polarizability of the cation.« less

Advances in aluminum hydroxide-based adjuvant research and its mechanism.

PubMed

He, Peng; Zou, Yening; Hu, Zhongyu

2015-01-01

In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants.

Advances in aluminum hydroxide-based adjuvant research and its mechanism

PubMed Central

He, Peng; Zou, Yening; Hu, Zhongyu

2015-01-01

In the past few decades, hundreds of materials have been tried as adjuvant; however, only aluminum-based adjuvants continue to be used widely in the world. Aluminum hydroxide, aluminum phosphate and alum constitute the main forms of aluminum used as adjuvants. Among these, aluminum hydroxide is the most commonly used chemical as adjuvant. In spite of its wide spread use, surprisingly, the mechanism of how aluminum hydroxide-based adjuvants exert their beneficial effects is still not fully understood. Current explanations for the mode of action of aluminum hydroxide-based adjuvants include, among others, the repository effect, pro-phagocytic effect, and activation of the pro-inflammatory NLRP3 pathway. These collectively galvanize innate as well as acquired immune responses and activate the complement system. Factors that have a profound influence on responses evoked by aluminum hydroxide-based adjuvant applications include adsorption rate, strength of the adsorption, size and uniformity of aluminum hydroxide particles, dosage of adjuvant, and the nature of antigens. Although vaccines containing aluminum hydroxide-based adjuvants are beneficial, sometimes they cause adverse reactions. Further, these vaccines cannot be stored frozen. Until recently, aluminum hydroxide-based adjuvants were known to preferentially prime Th2-type immune responses. However, results of more recent studies show that depending on the vaccination route, aluminum hydroxide-based adjuvants can enhance both Th1 as well as Th2 cellular responses. Advances in systems biology have opened up new avenues for studying mechanisms of aluminum hydroxide-based adjuvants. These will assist in scaling new frontiers in aluminum hydroxide-based adjuvant research that include improvement of formulations, use of nanoparticles of aluminum hydroxide and development of composite adjuvants. PMID:25692535

The effect of fly ash and coconut fibre ash as cement replacement materials on cement paste strength

NASA Astrophysics Data System (ADS)

Bayuaji, R.; Kurniawan, R. W.; Yasin, A. K.; Fatoni, H. AT; Lutfi, F. M. A.

2016-04-01

Concrete is the backbone material in the construction field. The main concept of the concrete material is composed of a binder and filler. Cement, concrete main binder highlighted by environmentalists as one of the industry are not environmentally friendly because of the burning of cement raw materials in the kiln requires energy up to a temperature of 1450° C and the output air waste CO2. On the other hand, the compound content of cement that can be utilized in innovation is Calcium Hydroxide (CaOH), this compound will react with pozzolan material and produces additional strength and durability of concrete, Calcium Silicate Hydrates (CSH). The objective of this research is to explore coconut fibers ash and fly ash. This material was used as cement replacement materials on cement paste. Experimental method was used in this study. SNI-03-1974-1990 is standard used to clarify the compressive strength of cement paste at the age of 7 days. The result of this study that the optimum composition of coconut fiber ash and fly ash to substitute 30% of cement with 25% and 5% for coconut fibers ash and fly ash with similar strength if to be compared normal cement paste.

Cytotoxicities and genotoxicities of cements based on calcium silicate and of dental formocresol.

PubMed

Ko, Hyunjung; Jeong, Youngdan; Kim, Miri

2017-03-01

Increasing interest is being paid to the toxicities of dental materials. The purpose of this study was to determine the cytotoxicities and genotoxicities of endodontic compounds to Chinese hamster ovary (CHO-K1) reproductive cells. Cultured CHO-K1 cells were treated with dental formocresol, two types of calcium hydroxide paste, and two types of mineral trioxide aggregate cement for 24h. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay was performed on each culture, and the micronucleus frequency was determined by performing a micronucleus assay. Alkaline comet assay and γ-H2AX immunofluorescence assay were used to detect DNA damage. Out of the five materials tested, only dental formocresol significantly increased DNA damage. The mineral trioxide aggregate cements based on calcium silicate were not found to be potentially genotoxic. The data suggest that dental formocresol should not be recommended for use in vital pulp therapy on young teeth. Copyright © 2017 Elsevier B.V. All rights reserved.

Dual nutraceutical nanohybrids of folic acid and calcium containing layered double hydroxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Tae-Hyun; Oh, Jae-Min, E-mail: jaemin.oh@yonsei.ac.kr

2016-01-15

Dual nutraceutical nanohybrids consisting of organic nutrient, folic acid (FA), and mineral nutrient, calcium, were prepared based on layered double hydroxide (LDH) structure. Among various hybridization methods such as coprecipitation, ion exchange, solid phase reaction and exfoliation-reassembly, it was found that exfoliation-reassembly was the most effective in terms of intercalation of FA moiety between Ca-containing LDH layers. X-ray diffraction patterns and infrared spectra indicated that FA molecules were well stabilized in the interlayer space of LDHs through electrostatic interaction. From the atomic force and scanning electron microscopic studies, particle thickness of LDH was determined to be varied with tens, amore » few and again tens of nanometers in pristine, exfoliated and reassembled state, respectively, while preserving particle diameter. The result confirmed layer-by-layer hybrid structure of FA and LDHs was obtained by exfoliation-reassembly. Solid UV–vis spectra showed 2-dimensional molecular arrangement of FA moiety in hybrid, exhibiting slight red shift in n→π* and π→π* transition. The chemical formulae of FA intercalated Ca-containing LDH were determined to Ca{sub 1.30}Al(OH){sub 4.6}FA{sub 0.74}·3.33H{sub 2}O and Ca{sub 1.53}Fe(OH){sub 5.06}FA{sub 2.24}·9.94H{sub 2}O by inductively coupled plasma-atomic emission spectroscopy, high performance liquid chromatography and thermogravimetry, showing high nutraceutical content of FA and Ca. - Highlights: • We successfully intercalated FA molecules into Ca-containing LDHs. • Exfoliation-reassembly was proven to be the most effective. • The interaction between LDH and FA were studied by FT-IR and UV–vis spectra. • Thermal stability of FA were enhanced by electrostatic interaction with LDH layers.« less

Process for the preparation of calcium superoxide

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Wood, P. C.; Wydeven, T. J.; Spitze, L. A. (Inventor)

1978-01-01

Calcium superoxide is prepared in high yields by spreading a quantity of calcium peroxide diperoxyhydrate on the surface of a container, positioning said container in a vacuum chamber on a support structure through which a coolant fluid can be circulated, partially evacuating said vacuum chamber, allowing the temperature of the diperoxyhydrate to reach the range of about 0 to about 40 C; maintaining the temperature selected for a period of time sufficient to complete the disproproriation of the diperoxyhydrate to calcium superoxide, calcium hydroxide, oxygen, and water; constantly and systematically removing the water as it is formed by sweeping the reacting material with a current of dry inert gas and/or by condensation of said water on a cold surface; backfilling the chamber with a dry inert gas; and finally, recovering the calcium superoxide produced.

Synthesis, spectroscopic and electrochemical performance of pasted β-nickel hydroxide electrode in alkaline electrolyte

NASA Astrophysics Data System (ADS)

Shruthi, B.; Bheema Raju, V.; Madhu, B. J.

2015-01-01

β-Nickel hydroxide (β-Ni(OH)2) was successfully synthesized using precipitation method. The structure and property of the β-Ni(OH)2 were characterized by X-ray diffraction (XRD), Fourier Transform infra-red (FT-IR), Raman spectra and thermal gravimetric-differential thermal analysis (TG-DTA). The results of the FTIR spectroscopy and TG-DTA studies indicate that the β-Ni(OH)2 contains water molecules and anions. The microstructural and composition studies have been performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. A pasted-type electrode is prepared using β-Ni(OH)2 powder as the active material on a nickel sheet as a current collector. Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) studies were performed to evaluate the electrochemical performance of the β-Ni(OH)2 electrode in 6 M KOH electrolyte. CV curves showed a pair of strong redox peaks as a result of the Faradaic redox reactions of β-Ni(OH)2. The proton diffusion coefficient (D) for the present β-Ni(OH)2 electrode material is found to be 1.44 × 10-12 cm2 s-1. Further, electrochemical impedance studies confirmed that the β-Ni(OH)2 electrode reaction processes are diffusion controlled.

Synthesis, spectroscopic and electrochemical performance of pasted β-nickel hydroxide electrode in alkaline electrolyte.

PubMed

Shruthi, B; Bheema Raju, V; Madhu, B J

2015-01-25

β-Nickel hydroxide (β-Ni(OH)2) was successfully synthesized using precipitation method. The structure and property of the β-Ni(OH)2 were characterized by X-ray diffraction (XRD), Fourier Transform infra-red (FT-IR), Raman spectra and thermal gravimetric-differential thermal analysis (TG-DTA). The results of the FTIR spectroscopy and TG-DTA studies indicate that the β-Ni(OH)2 contains water molecules and anions. The microstructural and composition studies have been performed using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis. A pasted-type electrode is prepared using β-Ni(OH)2 powder as the active material on a nickel sheet as a current collector. Cyclic voltammetry (CV) and Electrochemical impedance spectroscopy (EIS) studies were performed to evaluate the electrochemical performance of the β-Ni(OH)2 electrode in 6M KOH electrolyte. CV curves showed a pair of strong redox peaks as a result of the Faradaic redox reactions of β-Ni(OH)2. The proton diffusion coefficient (D) for the present β-Ni(OH)2 electrode material is found to be 1.44×10(-12) cm(2) s(-1). Further, electrochemical impedance studies confirmed that the β-Ni(OH)2 electrode reaction processes are diffusion controlled. Copyright © 2014 Elsevier B.V. All rights reserved.

Nickel hydroxide electrode. 3: Thermogravimetric investigations of nickel (II) hydroxides

NASA Technical Reports Server (NTRS)

Dennstedt, W.; Loeser, W.

1982-01-01

Water contained in Ni hydroxide influences its electrochemical reactivity. The water content of alpha and beta Ni hydroxides is different with respect to the amount and bond strength. Thermogravimetric experiments show that the water of the beta Ni hydroxides exceeding the stoichiometric composition is completely removed at 160 deg. The water contained in the interlayers of the beta hydroxide, however, is removed only at higher temperatures, together with the water originating from the decomposition of the hydroxide. These differences are attributed to the formation of II bonds within the interlayers and between interlayers and adjacent main layers. An attempt is made to explain the relations between water content and the oxidizability of the Ni hydroxides.

In Vitro Evaluation of Dentin Tubule Occlusion for Novel Calcium Lactate Phosphate (CLP) Paste

PubMed Central

Yang, Jen-Chang; Hu, Hsin-Tai; Lee, Sheng-Yang; Hsieh, Sung-Chih; Huang, Pei-Chi; Ma, Chen-Feng; Ji, Dian-Yu; Chang, Liang-Yu; Teng, Nai-Chia

2017-01-01

Introduction: The objective of this in vitro study is to evaluate the effective and long-term occlusion of dentinal tubules using a novel calcium lactate phosphate (CLP) based desensitizing agent. Methods: Dentin disks (n = 9) were pre-etched using 1 M lactic acid for 30 s and individually treated with Colgate® Pro-Relief™ paste, CLP paste, and double distilled water (ddH2O) by a rubber-cupped handpiece. Dentin disks were analyzed under optical micrographs for pre-treatment, directly after treatment, and 14 days post-treatment. One-way ANOVA and post-hoc Tukey’s test were used to determine whether there were any statistically significant differences in dentinal tubule diameter. Results: A significant decrease occurred in the mean tubule diameter for dentin disks treated with CLP paste. A decrease was observed from 3.52 ± 0.83 µm to 2.62 ± 0.42 µm right after treatment, further decreasing to 1.71 ± 0.45 µm after immersion in artificial saliva for 14 days (p < 0.05). Conclusions: The results suggest that the CLP based desensitizing paste has remineralization properties and provides instant and lasting effectiveness in dentinal tubule occlusion. PMID:28772594

Effectiveness of an in-office arginine-calcium carbonate paste on dentine hypersensitivity in periodontitis patients: a double-blind, randomized controlled trial.

PubMed

Pepelassi, Eudoxie; Rahiotis, Christos; Peponi, Eleni; Kakaboura, Afrodite; Vrotsos, Ioannis

2015-01-01

The aim of this single-centre, two-cell, double-blind, randomized controlled clinical study was to evaluate the effectiveness of an in-office desensitizing paste containing 8% arginine and calcium carbonate in providing relief on dentine hypersensitivity immediately after scaling and root planing and its sustained relief over a 6-week period. Fifty periodontitis subjects presenting hypersensitivity were subjected to scaling and root planing and in-office application of either 8% arginine and calcium carbonate desensitizing paste (25 subjects, test group) or fluoride-free prophylaxis paste (25 subjects, control group). Air-blast hypersensitivity was assessed using Schiff and Visual Analogue (VAS) scales at baseline, post-scaling, post-application, 2, 4 and 6 weeks. At all evaluation times, the test group presented significant % reduction in hypersensitivity relative to post-scaling (t-test, p < 0.05) (Schiff - Test: 57, 58.6, 60.2, 68; 28.6, 22.2, 23, 23) (VAS - Test: 60, 55.6, 60.1, 68.4; 25.9, 18.2, 20.6, 22.7) and significant % hypersensitivity difference relative to control (ancova, p < 0.05) (Schiff: 38.9, 45.9, 47.4, 57.7; VAS: 49.1, 48.9, 52.6, 61). The single in-office application of the 8% arginine-calcium carbonate desensitizing paste after scaling and root planing provided significant immediate reduction in dentine hypersensitivity, which sustained over a 6-week period. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Morphometric and microscopic evaluation of the effect of a solution of alendronate as an intracanal therapeutic agent in rat teeth submitted to late reimplantation.

PubMed

Mori, Graziela Garrido; Garcia, Roberto Brandão; Gomes de Moraes, Ivaldo; Bramante, Clóvis Monteiro; Bernardineli, Norberti

2007-08-01

The use of substances that inhibit root resorption may be an alternative for cases of unsuccessful reimplants. Hence, the purpose of this study was to test a solution of alendronate, a resorption inhibitor, as an intracanal therapeutic agent for teeth submitted to late reimplantation. Thirty rat maxillary right central incisors were avulsed and kept dry for 30 min. The teeth were instrumented, and the root surfaces treated with 1% hypochlorite solution followed by application of 2% sodium fluoride. Thereafter, the teeth were divided in two groups according to the intracanal dressing: (i) group I, solution of alendronate and (ii) group II, calcium hydroxide paste. Teeth were then reimplanted in their respective sockets. The animals were killed at 15, 30 and 60 days after reimplantation and the samples processed for morphometric and microscopic analysis. The results demonstrated that the solution of alendronate and the calcium hydroxide paste limited the root resorption, yet did not impair its occurrence. It may be concluded that alendronate and calcium hydroxide paste demonstrated similar behavior.

Prevention of the ingress of a known virulent bacterium into the root canal system by intracanal medications.

PubMed

Roach, R P; Hatton, J F; Gillespie, M J

2001-11-01

Contamination of the root canal system by persistent, enteric bacteria via leakage through interim restorations has been well documented. This in vitro study evaluated the ability of interappointment medications to prevent contamination of the root canal system by Enterococcus faecalis. Coronally unsealed, medicated tooth roots fixed in a closed system were contaminated daily with a standardized, aerobic, broth culture of E. faecalis. Four medications were evaluated (n = 15): group A, calcium hydroxide/methylcellulose paste; group B, camphorated parachlorophenol/calcium hydroxide paste; group C, 1% chlorhexidine/methylcellulose gel; and group D, calcium hydroxide points. The mean number of days to contamination as indicated by turbidity in the closed system was the following: group A, 37; group B, 46; group C, 16; group D, 5; and a positive control (no medication), 3. A one-way analysis of variance with a Scheffe post hoc test (p = 0.05) detected significant differences in effectiveness with A and B superior to C and D, and C superior to D.

Characterization of Chlorhexidine-Loaded Calcium-Hydroxide Microparticles as a Potential Dental Pulp-Capping Material.

PubMed

Priyadarshini, Balasankar M; Selvan, Subramanian T; Narayanan, Karthikeyan; Fawzy, Amr S

2017-06-22

This study explores the delivery of novel calcium hydroxide [Ca(OH)₂] microparticles loaded with chlorhexidine (CHX) for potential dental therapeutic and preventive applications. Herein, we introduce a new approach for drug-delivery to deep dentin-surfaces in the form of drug-loaded microparticles. Unloaded Ca(OH)₂ [Ca(OH)₂/Blank] and CHX-loaded/Ca(OH)₂ microparticles were fabricated by aqueous chemical-precipitation technique. The synthesized-microparticles were characterized in vitro for determination of surface-morphology, crystalline-features and thermal-properties examined by energy-dispersive X-ray scanning and transmission electron-microscopy (EDX-SEM/TEM), Fourier-transform infrared-spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning-calorimetry (DSC). Time-related pH changes, initial antibacterial/biofilm-abilities and cytotoxicity of CHX-loaded/Ca(OH)₂ microparticles were evaluated. Microparticles were delivered to dentin-surfaces with subsequent SEM examination of treated dentin-substrates. The in vitro and ex vivo CHX-release profiles were characterized. Ca(OH)₂/Blank were hexagonal-shaped with highest z -average diameter whereas CHX-inclusion evidenced micro-metric spheres with distinguishable surface "rounded deposits" and a negative-shift in diameter. CHX:Ca(OH)₂/50 mg exhibited maximum encapsulation-efficiency with good antibacterial and cytocompatible properties. SEM examination revealed an intact layer of microparticles on exposed dentin-surfaces with retention of spherical shape and smooth texture. Microparticles loaded on dentin-surfaces showed prolonged release of CHX indicating substantial retention on dentin-substrates. This study validated the inherent-applicability of this novel drug-delivery approach to dentin-surfaces using micro-metric CHX-loaded/Ca(OH)₂ microparticles.

Characterization of Chlorhexidine-Loaded Calcium-Hydroxide Microparticles as a Potential Dental Pulp-Capping Material

PubMed Central

Priyadarshini, Balasankar M.; Selvan, Subramanian T.; Narayanan, Karthikeyan; Fawzy, Amr S.

2017-01-01

This study explores the delivery of novel calcium hydroxide [Ca(OH)2] microparticles loaded with chlorhexidine (CHX) for potential dental therapeutic and preventive applications. Herein, we introduce a new approach for drug-delivery to deep dentin-surfaces in the form of drug-loaded microparticles. Unloaded Ca(OH)2 [Ca(OH)2/Blank] and CHX-loaded/Ca(OH)2 microparticles were fabricated by aqueous chemical-precipitation technique. The synthesized-microparticles were characterized in vitro for determination of surface-morphology, crystalline-features and thermal-properties examined by energy-dispersive X-ray scanning and transmission electron-microscopy (EDX-SEM/TEM), Fourier-transform infrared-spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and differential scanning-calorimetry (DSC). Time-related pH changes, initial antibacterial/biofilm-abilities and cytotoxicity of CHX-loaded/Ca(OH)2 microparticles were evaluated. Microparticles were delivered to dentin-surfaces with subsequent SEM examination of treated dentin-substrates. The in vitro and ex vivo CHX-release profiles were characterized. Ca(OH)2/Blank were hexagonal-shaped with highest z-average diameter whereas CHX-inclusion evidenced micro-metric spheres with distinguishable surface “rounded deposits” and a negative-shift in diameter. CHX:Ca(OH)2/50 mg exhibited maximum encapsulation-efficiency with good antibacterial and cytocompatible properties. SEM examination revealed an intact layer of microparticles on exposed dentin-surfaces with retention of spherical shape and smooth texture. Microparticles loaded on dentin-surfaces showed prolonged release of CHX indicating substantial retention on dentin-substrates. This study validated the inherent-applicability of this novel drug-delivery approach to dentin-surfaces using micro-metric CHX-loaded/Ca(OH)2 microparticles. PMID:28952538

ROS mediated high anti-bacterial efficacy of strain tolerant layered phase pure nano-calcium hydroxide.

PubMed

Samanta, Aniruddha; Podder, Soumik; Ghosh, Chandan Kumar; Bhattacharya, Manjima; Ghosh, Jiten; Mallik, Awadesh Kumar; Dey, Arjun; Mukhopadhyay, Anoop Kumar

2017-08-01

The present work provides the first ever report on extraordinarily high antibacterial efficacy of phase pure micro-layered calcium hydroxide nanoparticles (LCHNPs) even under dark condition. The LCHNPs synthesized especially in aqueous medium by a simple, inexpensive method show adequate mechanical properties along with the presence of a unique strain tolerant behaviour. The LCHNPs are characterized by FTIR, Raman spectroscopy, XRD, Rietveld analysis, FE-SEM, TEM, TG-DTA, surface area, particle size distribution, zeta potential analysis and nanoindentation techniques. The LCHNPs have 98.1% phase pure hexagonal Ca(OH) 2 as the major phase having micro-layered architecture made up of about ~100-200nm thick individual nano-layers. The nanomechanical properties e.g., nanohardness (H) and Young's modulus (E) of the LCHNPs are found to have a unique load independent behavior. The dielectric responses (e.g., dielectric constant and dielectric loss) and antibacterial properties are evaluated for such LCHNPs. Further, the LCHNPs show much better antibacterial potency against both gram-positive e.g., Staphylococcus aureus (S. aureus) and gram-negative e.g., Pseudomonas putida (P. putida) bacteria even in dark especially, with the lowest ever reported MIC value (e.g., 1 μg ml -1 ) against the P. putida bacterial strain and exhibit ROS mediated antibacterial proficiency. Finally, such LCHNPs has almost ~8-16% inhibition efficacy towards the development of biofilm of these microorganisms quantified by colorimetric detection process. So, such LCHNPs may find potential applications in the areas of healthcare industry and environmental engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extent and mechanism of phase separation during the extrusion of calcium phosphate pastes.

PubMed

O'Neill, Rory; McCarthy, Helen O; Cunningham, Eoin; Montufar, Edgar; Ginebra, Maria-Pau; Wilson, D Ian; Lennon, Alex; Dunne, Nicholas

2016-02-01

The aim of this study was to increase understanding of the mechanism and dominant drivers influencing phase separation during ram extrusion of calcium phosphate (CaP) paste for orthopaedic applications. The liquid content of extrudate was determined, and the flow of liquid and powder phases within the syringe barrel during extrusion were observed, subject to various extrusion parameters. Increasing the initial liquid-to-powder mass ratio, LPR, (0.4-0.45), plunger rate (5-20 mm/min), and tapering the barrel exit (45°-90°) significantly reduced the extent of phase separation. Phase separation values ranged from (6.22 ± 0.69 to 18.94 ± 0.69 %). However altering needle geometry had no significant effect on phase separation. From powder tracing and liquid content determination, static zones of powder and a non-uniform liquid distribution was observed within the barrel. Measurements of extrudate and paste LPR within the barrel indicated that extrudate LPR remained constant during extrusion, while LPR of paste within the barrel decreased steadily. These observations indicate the mechanism of phase separation was located within the syringe barrel. Therefore phase separation can be attributed to either; (1) the liquid being forced downstream by an increase in pore pressure as a result of powder consolidation due to the pressure exerted by the plunger or (2) the liquid being drawn from paste within the barrel, due to suction, driven by dilation of the solids matrix at the barrel exit. Differentiating between these two mechanisms is difficult; however results obtained suggest that suction is the dominant phase separation mechanism occurring during extrusion of CaP paste.

The effect of dentin on the pulp tissue dissolution capacity of sodium hypochlorite and calcium hydroxide.

PubMed

Slutzky-Goldberg, Iris; Hanut, Aiham; Matalon, Shlomo; Baev, Valery; Slutzky, Hagay

2013-08-01

Sodium hypochlorite (NaOCl) and calcium hydroxide (Ca[OH]2) have tissue dissolution capacity. The aim of this study was to evaluate the potential effect of dentin on their tissue dissolution capacity in a novel dentin model. Dentin models were prepared from 25 freshly extracted human molar teeth; the crowns were separated from the roots, and a rectangular inner shape was prepared. Pulp tissue samples adjusted to similar weights of 6.5 ± 0.2 mg were randomly divided into 6 groups: NaOCl groups in test tubes or dentin models for 1 hour, Ca(OH)2 groups in test tubes or dentin models for 1 week, and control groups saline in test tubes or dentin models for 1 week. The final weights after the experimental period were checked and compared with the initial weights. The differences were statistically analyzed. The tissue dissolution capacity of Ca(OH)2 was affected by the presence of dentin. Similarly, NaOCl lost its effect on the pulp tissue after incubation in dentin. Comparison between all test groups showed highly significant differences (P < .001). Dentin has a detrimental effect on the ability of NaOCl and Ca(OH)2 to dissolve pulp tissue. The dentin model appears to be an efficient tool for the study of interactions between local endodontic medicaments, dentin, and pulp tissue. Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Removal of calcium hydroxide from Weine Type II systems using photon-induced photoacoustic streaming, passive ultrasonic, and needle irrigation: a microcomputed tomography study

PubMed Central

LLOYD, Adam; NAVARRETE, Geraldine; MARCHESAN, Melissa Andreia; CLEMENT, David

2016-01-01

ABSTRACT Objective This study compared the effectiveness of Er:YAG laser-activated irrigation (PIPS), passive ultrasonic irrigation (PUI) with EndoUltra and standard needle irrigation (SNI) in the removal of calcium hydroxide [Ca(OH)2] from the mesial roots of Weine Type II mandibular molars. Material and Methods Thirty mandibular molars were screened by µCT for the presence of mesial roots with complex intra-canal anatomy and a common apical foramen. The teeth were enlarged to a standardized 25/.06 preparation and filled with Ca(OH)2 paste. Specimens were divided into three groups (n=10) according to the technique used for Ca(OH)2 removal: PIPS, at 15 Hz and 20 mJ using a 9 mm long, 600 µm diameter tip; PUI using a 15/.02 tip; and SNI (30 Ga. side-vented needle). Equal volumes of 8.25% NaOCl and 17% EDTA were used in all groups. µCT was used to measure the initial amount of Ca(OH)2 present and to assess the residual volume of Ca(OH)2 following each irrigation protocol. Data were analyzed using Tukey HSD and Kruskal-Wallis tests (α=5%). Results The mean volume of Ca(OH)2 before removal was significantly higher in the coronal third than in the middle and apical third (p<0.001). Ca(OH)2 was similarly removed from the coronal and middle thirds with the three methods used (p>0.05). PIPS (median 0%; IQR: 0-0) showed significant higher Ca(OH)2 removal in the apical third than PUI (median 100%, IQR: 85-100) and SNI (median 47%; IQR: 16-72) (p<0.001). Conclusions PIPS laser-activation was more effective for the removal of Ca(OH)2 from mesial roots of mandibular molars with Weine Type II canal configurations than PUI with EndoUltra and SNI. PMID:28076457

The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate

PubMed Central

Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

2016-01-01

The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns. PMID:27023532

The Retentive Strength of Cemented Zirconium Oxide Crowns after Dentin Pretreatment with Desensitizing Paste Containing 8% Arginine and Calcium Carbonate.

PubMed

Pilo, Raphael; Harel, Noga; Nissan, Joseph; Levartovsky, Shifra

2016-03-25

The effect of dentin pretreatment with Desensitizing Paste containing 8% arginine and calcium carbonate on the retention of zirconium oxide (Y-TZP) crowns was tested. Forty molar teeth were mounted and prepared using a standardized protocol. Y-TZP crowns were produced using computer-aided design and computer-aided manufacturing (CAD-CAM) technology. The 40 prepared teeth were either pretreated with Desensitizing Paste or not pretreated. After two weeks, each group was subdivided into two groups, cemented with either Resin Modified Glass Ionomer Cement (RMGIC) or Self Adhesive Resin Cement (SARC)). Prior to cementation, the surface areas of the prepared teeth were measured. After aging, the cemented crown-tooth assemblies were tested for retentive strength using a universal testing machine. The debonded surfaces of the teeth and crowns were examined microscopically at 10× magnification. Pretreating the dentin surfaces with Desensitizing Paste prior to cementation did not affect the retention of the Y-TZP crowns. The retentive values for RMGIC (3.04 ± 0.77 MPa) were significantly higher than those for SARC (2.28 ± 0.58 MPa). The predominant failure modes for the RMGIC and SARC were adhesive cement-dentin and adhesive cement-crown, respectively. An 8.0% arginine and calcium carbonate in-office desensitizing paste can be safely used to reduce post-cementation sensitivity without reducing the retentive strength of Y-TZP crowns.

Magnesium Hydroxide

MedlinePlus

Magnesium hydroxide is used on a short-term basis to treat constipation.This medication is sometimes prescribed ... Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as ...

Aluminum Hydroxide

MedlinePlus

Aluminum hydroxide is used for the relief of heartburn, sour stomach, and peptic ulcer pain and to ... Aluminum hydroxide comes as a capsule, a tablet, and an oral liquid and suspension. The dose and ...

Antiwashout behavior of calcium phosphate cement incorporated with Poly(ethylene glycol)

NASA Astrophysics Data System (ADS)

Hablee, S.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.

2018-01-01

The effect of powder-to-liquid ratio and addition of poly(ethylene glycol) on the antiwashout behavior of calcium phosphate cement has been investigated. Calcium hydroxide, Ca(OH)2, and diammonium hydrogen phosphate, (NH4)2HPO4, were used as precursors with distilled water as the solvent in the wet chemical precipitation synthesis of hydroxyapatite powder. Cement paste was prepared by mixing the as-synthesized powder with distilled water at certain ratios, varied at 1.0, 1.3, 1.5 and 1.6. Poly(ethylene glycol) was added into distilled water, varied at 1, 2, 3, 4 and 5 wt% using the powder-to-liquid ratio of 1.3. The antiwashout properties of the cement has been investigated by soaking in Ringer’s solution for 3 and 7 days. The evolution of compressive strength of calcium phosphate cement before and after soaking have been determined. After 7 days soaking, the strength of the cement increased by 94.4%, 2.98%, 11.39% and 111.29% for powder-to-liquid ratios 1.0, 1.3, 1.5 and 1.6 respectively. The addition of poly(ethylene glycol) up to 3% shows an increase in strength after 7 days soaking, with 57.75%, 16.4% and 19.97% increase for 1, 2 and 3% poly(ethylene glycol) contents respectively. The calcium phosphate cement produced in this current study shows excellent antiwashout behavior since no cement dissolution happened and the compressive strength of the cement increased with soaking time throughout 7 days soaking in Ringer’s solution.

Removal efficiency of calcium hydroxide dressing from the root canal without chemically active adjuvant.

PubMed

Maalouf, Lara; Zogheib, Carla; Naaman, Alfred

2013-03-01

Compare the efficiency in removing two calcium hydroxide [Ca(OH)2] preparations from root canal and apical third using single use syringe, ultrasonics and RinsEndo((®)) with saline solution. One hundred and eighty human singlerooted teeth were instrumented using ProTaper((®)) rotary system, divided into two groups according to Ca(OH)2 filling. A: Powder mixed with water, B: Pulpdent((®)). Each group was divided into three subgroups for the irrigation: A1, B1: Single use syringe; A2, B2: Ultrasonics; A3, B3: RinsEndo((®)). Teeth were split longitudinally, photographed and imported into Adobe Photoshop. The percentage ratios of Ca(OH)2 remaining in the canal and in the apical third were calculated. Data were statistically analyzed using 'ANOVA two-way' and 'univariate tests'. (a) Remnants of medicament were found in all teeth, (b) no statistically significant difference in the elimination of both Ca(OH)2 from the entire canal (p = 0.436), however, mixed powder was better eliminated from the apical third (p = 0.005), (c) no statistically significant difference among the irrigation techniques in the whole canal (p = 0.608), though, RinsEndo((®)) and ultrasonics were the most effective in cleaning the apical third (p = 0.032) when mixed powder was used. None of the techniques removed completely Ca(OH)2 from the canal. In the apical third, RinsEndo((®)) and ultrasonics were the most effective when mixed powder was used. Ca(OH)2, the most commonly used intracanal dressing, should be completely eliminated before the obturation to assure a good endodontic sealing. Based on the results of this study, RinsEndo((®)) and ultrasonics were the most effective in removal of Ca(OH)2 especially the powder mixed with water presentation.

Interactions between iron(III)-hydroxide polymaltose complex and commonly used medications / laboratory studies in rats.

PubMed

Funk, Felix; Canclini, Camillo; Geisser, Peter

2007-01-01

Simple iron salts, such as iron sulphate, often interact with food and other medications reducing bioavailability and tolerability. Iron(III)-hydroxide polymaltose complex (IPC, Maltofer) provides a soluble form of non-ionic iron, making it an ideal form of oral iron supplementation. The physicochemical properties of IPC predict a low potential for interactions. The effects of co-administration with aluminium hydroxide (CAS 21645-51-2), acetylsalicylic acid (CAS 50-78-2), bromazepam (CAS 1812-30-2), calcium acetate (CAS 62-54-4), calcium carbonate (CAS 471-34-1), auranofin (CAS 34031-32-8), magnesium-L-aspartate hydrochloride (CAS 28184-71-6), methyldopa sesquihydrate (CAS 41372-08-1), paracetamol (CAS 103-90-2), penicillamine (CAS 52-67-5), sulfasalazine (CAS 599-79-1), tetracycline hydrochloride (CAS 64-75-5), calcium phosphate (CAS 7757-93-9) in combination with vitamin D3 (CAS 67-97-0), and a multi-vitamin preparation were tested in rats fed an iron-deficient diet. Uptake of iron from radiolabelled IPC with and without concomitant medications was compared. None of the medicines tested had a significant effect on iron uptake. Iron-59 retrieval from blood and major storage organs was 64-76% for IPC alone compared with 59-85% following co-administration with other medications. It is concluded that, under normal clinical conditions, IPC does not interact with these medications.

Effects of calcium leaching on diffusion properties of hardened and altered cement pastes

NASA Astrophysics Data System (ADS)

Kurumisawa, Kiyofumi; Haga, Kazuko; Hayashi, Daisuke; Owada, Hitoshi

2017-06-01

It is very important to predict alterations in the concrete used for fabricating disposal containers for radioactive waste. Therefore, it is necessary to understand the alteration of cementitious materials caused by calcium leaching when they are in contact with ground water in the long term. To evaluate the long-term transport characteristics of cementitious materials, the microstructural behavior of these materials should be considered. However, many predictive models of transport characteristics focus on the pore structure, while only few such models consider both, the spatial distribution of calcium silicate hydrate (C-S-H), portlandite, and the pore spaces. This study focused on the spatial distribution of these cement phases. The auto-correlation function of each phase of cementitious materials was calculated from two-dimensional backscattered electron imaging, and the three-dimensional spatial image of the cementitious material was produced using these auto-correlation functions. An attempt was made to estimate the diffusion coefficient of chloride from the three-dimensional spatial image. The estimated diffusion coefficient of the altered sample from the three-dimensional spatial image was found to be comparable to the measured value. This demonstrated that it is possible to predict the diffusion coefficient of the altered cement paste by using the proposed model.

Effectiveness of various irrigation protocols for the removal of calcium hydroxide from artificial standardized grooves

PubMed Central

GOKTURK, Hakan; OZKOCAK, Ismail; BUYUKGEBIZ, Feyzi; DEMIR, Osman

2017-01-01

Abstract Objective The aim of this study was to investigate the ability of laser-activated irrigation (LAI), XP-endo Finisher, CanalBrush, Vibringe, passive ultrasonic irrigation (PUI), and conventional syringe irrigation systems on the removal of calcium hydroxide (CH) from simulated root canal irregularities. Material and Methods The root canals of one hundred and five extracted single-rooted teeth were instrumented using Reciproc rotary files up to size R40. The teeth were split longitudinally. Two of the three standard grooves were created in the coronal and apical section of one segment, and another in the middle part of the second segment. The standardized grooves were filled with CH and the root halves were reassembled. After 14 days, the specimens were randomly divided into 7 experimental groups (n=15/group). CH was removed as follows: Group 1: beveled needle irrigation; Group 2: double side-vented needle irrigation; Group 3: CanalBrush; Group 4: XP-endo Finisher; Group 5: Vibringe; Group 6: PUI; Group 7: LAI. The amount of remaining CH in the grooves was scored under a stereomicroscope at 20× magnification. Statistical evaluation was performed using Kruskal–Wallis and Bonferroni-Correction Mann–Whitney U tests. Results Groups 1 and 2 were the least efficient in eliminating CH from the grooves. Groups 6 and 7 eliminated more CH than the other protocols; however, no significant differences were found between these two groups (P>.05). Conclusions Nevertheless, none of the investigated protocols were able to completely remove all CH from all three root regions. LAI and PUI showed less residual CH than the other protocols from artificial grooves. PMID:28678948

Clinical and radiographic evaluation of indirect pulp treatment with MTA and calcium hydroxide in primary teeth (in-vivo study).

PubMed

George, Vimi; Janardhanan, Suresh Kumar; Varma, Balagopal; Kumaran, Parvathy; Xavier, Arun Mamachan

2015-01-01

Clinical and radiographic effects of mineral trioxide aggregate (white MTA) and calcium hydroxide (Dycal) in indirect pulp treatment (IPT) of primary teeth over a period of 6 months. A clinical trial with sample size of 40 primary molars between the age group of 5-9 years, of which, 20 teeth were considered, each for MTA and Dycal. Measurements on the digitized radiographs were performed at baseline, third and sixth month, increase in dentin was then measured using Corel Draw software. Independent t-test had indicated that at the end of 3 months and 6 months, a statistically significant increase in dentin thickness with both MTA and Dycal (P-value ≤ 0.001) was found. Within the MTA group, the thickness of dentin formed was 0.089 mm ± 0.031 mm at first 3 months and 0.055 ± 0.022 mm at the second 3 months, (P ≤ 0.001) evaluated using paired t-test. In the Dycal group, increment in dentin deposited was 0.068 mm at the first 3 months and second 3 months, it was 0.030 mm (P-value ≤ 0.001). Clinically and radiographically, MTA is superior to Dycal as a good IPT medicament in primary teeth.

Antimicrobial Efficacy of Octenidine Hydrochloride and Calcium Hydroxide with and Without a Carrier: A Broth Dilution Analysis.

PubMed

Varghese, Vinaya Susan; Uppin, Veerendra; Bhat, Kishore; Pujar, Madhu; Hooli, Amruta B; Kurian, Nirmal

2018-01-01

An efficient antimicrobial agent action is required for a predetermined time period for absolute elimination of root canal microbes. Till date, there is limited or no data on the antimicrobial effect of octenidine as an intracanal medicament with chitosan (CTS) as a carrier against Candida albicans and Enterococcus faecalis . The aim of this microbiological study was to compare the antimicrobial efficacy of octenidine hydrochloride (OHC) and calcium hydroxide (Ca[OH] 2 ) as intracanal medicaments, both independently and along with CTS as a carrier molecule against the common resistant endodontic pathogens. A total of 160 single-rooted anterior teeth were selected, root canal preparation was done, and teeth were divided into two groups and contaminated with C. albicans and E. faecalis , which were further divided into four test groups each according to intracanal medicaments used. CTS was used as a vehicle for OHC and Ca(OH) 2 and antimicrobial assessment was performed on day 2 and day 7 following broth dilution method. Dentine samples were collected after each time interval, and the number of colony-forming units was determined. All four medicaments used in this study showed antifungal and antibacterial activity that diminished from day 2 to day 7. Group I (OHC alone) and Group IV (Ca[OH] 2 alone) showed significant antimicrobial activity against C. albicans and E. faecalis , respectively, than the other groups. A combination of OHC + CTS and Ca(OH) 2 + CTS produced inferior results than that of the medicaments used alone.

Ammonium hydroxide poisoning

MedlinePlus

Ammonium hydroxide is a colorless liquid chemical solution. It is in a class of substances called caustics. Ammonium hydroxide forms when ammonia dissolves in water. This article discusses poisoning from ...

Antimicrobial potential of medicaments used in healing process in dogs' teeth with apical periodontitis.

PubMed

Estrela, Carlos; Holland, Roberto; Bernabé, Pedro Felício Estrada; de Souza, Valdir; Estrela, Cyntia R A

2004-01-01

The objective of this study was to evaluate the influence of irrigants on the antimicrobial potential of calcium hydroxide paste in dogs' teeth with apical periodontitis. Forty-eight premolar teeth of adult mongrel dogs had their root canals opened to the oral environment for 6 months. The root canals were prepared and treated with different irrigating solutions and intracanal medicaments, according to the following groups: 1) 2.5% sodium hypochlorite (NaOCl) + calcium hydroxide paste (CHP); 2) 2% chlorhexidine (CHX) + CHP; 3) vinegar + CHP; 4) vinegar + vinegar. In group 4, both the irrigating solution and intracanal medicament were vinegar, which was renewed every 7 days. Each sample was collected by using two paper points maintained in position for 1 min, and individually transported and immersed in 7 mL of Letheen broth (LB), followed by incubation at 37 degrees C for 48 h. Microbial growth was analyzed by two methods: turbidity of the culture medium and subculture on a specific nutrient broth (brain heart infusion). After 21 days, all experimental groups had microbial growth, however, in different percentages: group 1 - 30%; group 2 - 30%; group 3 - 40%; group 4 - 60%. All materials tested had antimicrobial potential; however, the influence of calcium hydroxide paste on the control of microorganisms must be remembered.

Sodium hydroxide poisoning

MedlinePlus

Sodium hydroxide is a very strong chemical. It is also known as lye and caustic soda. This ... poisoning from touching, breathing in (inhaling), or swallowing sodium hydroxide. This article is for information only. Do ...

Efficacy of sodium hypochlorite, ethylenediaminetetraacetic acid, citric acid and phosphoric acid in calcium hydroxide removal from the root canal: a microscopic cleanliness evaluation.

PubMed

da Silva, Juliana Melo; Silveira, Amanda; Santos, Elizandra; Prado, Laiìs; Pessoa, Oscar F

2011-12-01

Rooted molars were subjected to standardized canal instrumentation to a master apical file (MAF). The samples were dressed with Ca(OH)(2), and after 7 days, teeth were reopened and Ca(OH)(2) medication was removed by 1 of 4 different experimental procedures: 2.5% sodium hypochlorite (NaOCl) (n = 10); 17% EDTA-T (n = 10); 10% citric acid (n = 10); or 37% phosphoric acid (n = 10). This was followed by reinstrumentation with MAF plus 15 mL saline solution. The roots were prepared for scanning electron microscopic analysis of the cervical, middle, and apical thirds. Statistical analysis was performed with the Kruskal-Wallis test. EDTA-T and phosphoric acid gave the best results in the apical third, with significant statistical differences compared with other groups. NaOCl gave the worst results. Irrigation with 17% EDTA-T and 37% phosphoric acid is more effective than sodium hypochlorite and citric acid in the removal of calcium hydroxide from the apical third. Copyright © 2011 Mosby, Inc. All rights reserved.

Direct Pulp Capping with Calcium Hydroxide, Mineral Trioxide Aggregate, and Biodentine in Permanent Young Teeth with Caries: A Randomized Clinical Trial.

PubMed

Brizuela, Claudia; Ormeño, Andrea; Cabrera, Carolina; Cabezas, Roxana; Silva, Carolina Inostroza; Ramírez, Valeria; Mercade, Montse

2017-11-01

Direct pulp capping treatment is intended to preserve pulp vitality, to avoid or retard root canal treatment, and, in cases with an open apex, to allow continued root development. Historically, calcium hydroxide (CH) was the gold standard material, but nowadays calcium silicate materials (CSMs) are displacing CH because of their high bioactivity, biocompatibility, sealing ability, and mechanical properties. However, more randomized clinical trials are needed to confirm the appropriateness of CSMs as replacement materials for CH in direct pulp capping procedures. A randomized clinical trial was conducted that included 169 patients (mean age, 11.3 years) from the Maipo district (Chile). The inclusion criterion was patients with 1 carious permanent tooth with pulpal exposure, a candidate for a direct pulp capping procedure. The patients were randomly allocated to one of the experimental groups (CH, Biodentine, or mineral trioxide aggregate [MTA]). Clinical follow-up examinations were performed at 1 week, 3 months, 6 months, and 1 year. The Fisher exact test was performed. At the follow-up examination at 1 week, the patients showed 100% clinical success. At 3 months, there was 1 failure in the CH group. At 6 months, there were 4 new failures (1 in the CH group and 3 in the MTA group). At 1 year, there was another failure in the CH group. There were no statistically significant differences among the experimental groups. CSMs appear to be suitable materials to replace CH. Although no significant differences were found among the materials studied, Biodentine and MTA offered some advantages over CH. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of substrate nature on the electrochemical deposition of calcium-deficient hydroxyapatites

NASA Astrophysics Data System (ADS)

Gualdrón-Reyes, A. F.; Domínguez-Vélez, V.; Morales-Morales, J. A.; Cabanzo, R.; Meléndez, A. M.

2017-01-01

Calcium phosphates were obtained by reducing nitrate ions to produce hydroxide ions on TiO2/stainless steel and TiO2/titanium electrodes. TiO2 coatings on metallic substrates were prepared by sol-gel dip-coating method. The morphology of deposits was observed by FESEM. Chemical nature of calcium phosphate deposits was identified by Raman micro-spectroscopy and FESEM/EDS microanalysis. Electrochemical behavior of nitrate and nitrite reduction on stainless steel and titanium electrodes was studied by linear sweep voltammetry. In addition, voltammetric study of the calcium phosphate electrodeposition on both electrodes was performed. From these measurements was selected the potential to form a calcium phosphate. A catalytic current associated to nitrate reduction reaction was obtained for stainless steel electrode, leading to significant deposition of calcium phosphate. Ca/P ratio for both substrates was less than 1.67. The formation of calcium deficient hydroxyapatite was confirmed by Raman spectroscopy.

Antimicrobial Efficacy of Octenidine Hydrochloride and Calcium Hydroxide with and Without a Carrier: A Broth Dilution Analysis

PubMed Central

Varghese, Vinaya Susan; Uppin, Veerendra; Bhat, Kishore; Pujar, Madhu; Hooli, Amruta B.; Kurian, Nirmal

2018-01-01

Background: An efficient antimicrobial agent action is required for a predetermined time period for absolute elimination of root canal microbes. Till date, there is limited or no data on the antimicrobial effect of octenidine as an intracanal medicament with chitosan (CTS) as a carrier against Candida albicans and Enterococcus faecalis. Aim: The aim of this microbiological study was to compare the antimicrobial efficacy of octenidine hydrochloride (OHC) and calcium hydroxide (Ca[OH]2) as intracanal medicaments, both independently and along with CTS as a carrier molecule against the common resistant endodontic pathogens. Materials and Methods: A total of 160 single-rooted anterior teeth were selected, root canal preparation was done, and teeth were divided into two groups and contaminated with C. albicans and E. faecalis, which were further divided into four test groups each according to intracanal medicaments used. CTS was used as a vehicle for OHC and Ca(OH)2 and antimicrobial assessment was performed on day 2 and day 7 following broth dilution method. Dentine samples were collected after each time interval, and the number of colony-forming units was determined. Results: All four medicaments used in this study showed antifungal and antibacterial activity that diminished from day 2 to day 7. Group I (OHC alone) and Group IV (Ca[OH]2 alone) showed significant antimicrobial activity against C. albicans and E. faecalis, respectively, than the other groups. Conclusion: A combination of OHC + CTS and Ca(OH)2+ CTS produced inferior results than that of the medicaments used alone. PMID:29599588

Production of edible carbohydrates from formaldehyde in a spacecraft. pH variations in the calcium hydroxide catalyzed formose reaction. Final Report, 1 Jul. 1973 - 30 Jun. 1974. M.S. Thesis

NASA Technical Reports Server (NTRS)

Weiss, A. H.; Kohler, J. T.; John, T.

1974-01-01

The study of the calcium hydroxide catalyzed condensation of formaldehyde was extended to a batch reactor system. Decreases in pH were observed, often in the acid regime, when using this basic catalyst. This observation was shown to be similar to results obtained by others using less basic catalysts in the batch mode. The relative rates of these reactions are different in a batch reactor than in a continuous stirred tank reactor. This difference in relative rates is due to the fact that at any degree of advancement in the batch system, the products have a history of previous products, pH, and dissolved catalyst. The relative rate differences can be expected to yield a different nature of product sugars for the two types of reactors.

Contribution to the knowledge of nickel hydroxide electrodes. 5. Analysis and electrochemical behavior of cadmium nickel hydroxides

NASA Technical Reports Server (NTRS)

Bode, H.; Dennstedt, W.

1981-01-01

Electrochemical experiments performed at sintered and bulk electrodes show that beta nickel hydroxide contains an electrochemically inactive proportion of cadmium hydroxide of up to 10%. The electrochemically ineffective cadmium hydroxide is homogeneously dissolved in beta nickel hydroxide.

Precipitation and Solubility of Calcium Hydrogenurate Hexahydrate

PubMed Central

Babić-Ivančić, V.; Füredi-Milhofer, H.; Brničević, N.; Marković, M.

1992-01-01

Solid phases formed in the quaternary system: uric acid—calcium hydroxide —hydrochloric acid—water aged for 2 months at 310 K were studied to determine conditions for calcium hydrogenurate hexahydrate, Ca(C5H3N4O)2 · 6H2O precipitation. The precipitates were identified by chemical and thermogravimetric analyses, x-ray powder diffraction, infrared spectroscopy, light microscopy, and scanning electron microscopy. In the precipitation diagram the concentration region in which calcium hydrogenurate hexahydrate precipitated as a single solid phase was established. The solubility of calcium hydrogenurate hexahydrate was investigated in the pH range from 6.2 to 10.1 at different temperatures. The total soluble and ionic concentration of calcium (atomic absorption spectroscopy and Ca-selective electrode), total urate concentration (spectrophotometry), and pH were determined in equilibrated solutions. The data are presented in the form of tables and chemical potential diagrams. By using these data the thermodynamic solubility products of calcium hydrogenurate hexahydrate, Ks = a(Ca2+) · a2(C5H3N4O3−), were determined: pKs=10.12±0.07at288K,pKs=9.81±0.09at298K,pKs=9.28±0.04at310K,andpKs=9.01±0.03at318K.The formation of calcium hydrogenurate hexahydrate crystals in urinary tract of patients with pathologically high concentrations of calcium and urates (hypercalciuria and hyperuricosiuria) is possible. PMID:28053438

ACTIVATION AND REACTIVITY OF NOVEL CALCIUM-BASED SORBENTS FOR DRY SO2 CONTROL IN BOILERS

EPA Science Inventory

Chemically modified calcium hydroxide (Ca(OH)2) sorbents developed in the U.S. Environmental Protection Agency's Air and Energy Engineering Research Laboratory (AEERL) for sulfur dioxide (SO2) control in utility boilers were tested in an electrically heated, bench-scale isotherma...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... Listing of Specific Substances Affirmed as GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide..., including pellets, flakes, sticks, lumps, and powders. Potassium hydroxide is obtained commercially from the...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... is prepared as a white precipitate by the addition of sodium hydroxide to a water soluble magnesium... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Potassium hydroxide. 184.1631 Section 184.1631... GRAS § 184.1631 Potassium hydroxide. (a) Potassium hydroxide (KOH, CAS Reg. No. 1310-58-3) is also... powders. Potassium hydroxide is obtained commercially from the electrolysis of potassium chloride solution...

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... addition of sodium hydroxide to a water soluble magnesium salt or by hydration of reactive grades of... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS Reg. No. 1309-42-8) occurs...

Process for decontaminating radioactive liquids using a calcium cyanamide-containing composition. [Patent application

DOEpatents

Silver, G.L.

1980-09-24

The present invention provides a process for decontaminating a radioactive liquid containing a radioactive element capable of forming a hydroxide. This process includes the steps of contacting the radioactive liquid with a decontaminating composition and separating the resulting radioactive sludge from the resulting liquid. The decontaminating composition contains calcium cyanamide.

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements.

PubMed

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-13

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter ( n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA ( p < 0.05) while maximum calcium ion release was dependent on Vol of TSC ( p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution ( p < 0.05).

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements

PubMed Central

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-01

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter (n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA (p < 0.05) while maximum calcium ion release was dependent on Vol of TSC (p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution (p < 0.05). PMID:29342837

Short-term vs long-term calcium hydroxide therapy after immediate tooth replantation: a histomorphometric study in monkey's teeth.

PubMed

Panzarini, Sônia Regina; Gulinelli, Jéssica Lemos; Saito, Célia T M H; Poi, Wilson Roberto; Sonoda, Celso Koogi; Américo de Oliveira, José; Melo, Moriel Evangelista; de Souza Gomes, Weglis Dyanne

2012-06-01

Endodontic treatment is an important step of tooth replantation protocols, but the ideal moment for definitive obturation of replanted teeth has not yet been established. In this study, a histomorphometric analysis was undertaken to evaluate the repair process on immediate replantation of monkey's teeth after calcium hydroxide (CH) therapy for 1 and 6 months followed by root canal filling with a CH-based sealer (Sealapex(®) ). The maxillary and mandibular lateral incisors of five female Cebus apella monkeys were extracted, kept in sterile saline for 15 min, replanted and splinted with stainless steel orthodontic wire and composite resin for 10 days. In Group I (control), definitive root canal filling was performed before tooth extraction. In Groups II and III, CH therapy started after removal of splint, and definitive root canal filling was performed 1 and 6 months later, respectively. The animals were euthanized 9 months after replantation, and specimens were processed for histomorphometric analysis. In all groups, epithelial attachment occurred at the cementoenamel junction or very close to this region; the areas of resorption on root surface had small extension and depth and were repaired by newly formed cementum; and the periodontal ligament was organized. Statistical analysis of the scores obtained for the histomorphometric parameters did not show any statistically significant difference (P = 0.1221) among the groups. The results suggests that when endodontic treatment is initiated 10 days after immediate replantation and an antibiotic regimen is associated, definitive root canal filling can be performed after a short-term CH therapy. © 2011 John Wiley & Sons A/S.

Calcium impregnation of coal enriched in CO.sub.2 using high-pressure techniques

NASA Technical Reports Server (NTRS)

Gavalas, George R. (Inventor); Sharma, Pramod K. (Inventor); Voecks, Gerald E. (Inventor)

1990-01-01

Methods are described for impregnating coal with calcium carbonate by utilizing an aqueous phase ionic reaction between calcium acetate, calcium hydroxide, and water with CO.sub.2 contained within the coal. The coal is enriched in CO.sub.2 by contacting it with CO.sub.2 at high pressure, in either a continuous or pulsed mode. The inclusion of CO.sub.2 in the coal during the process does not involve evacuating the coal and subsequently absorbing CO.sub.2 onto the coal as in prior methods. Rather, the coal is treated with carbon dioxide at high pressure in a practical and viable approach. The impregnation of coal by calcium compounds not only reduces sulfur emissions by effectively tying up the sulfur as calcium sulfide or sulfate, but also increases the gasification or combustion rate. The invention also encompasses the use of other Group IIA elements, as well as the coal products resulting from the methods of treatment described.

In Vivo Effect of Calcium Hydroxide and Resin-modified Glass Ionomer Cement on Carious Dentin in Young Permanent Molars: An Ultrastructural and Macroscopic Study.

PubMed

Opal, Shireen; Garg, Shalini; Sharma, Deepak; Dhindsa, Abhishek; Jatana, Isha

2017-01-15

The purpose of this study was to evaluate macroscopically and ultrastructurally the effect of calcium hydroxide cement (CH) and resin-modified glass ionomer cement (RMGIC) compared with gutta percha (control) as a lining material on carious dentin after partial caries removal and sealing. Twenty-seven permanent molars with deep carious lesions underwent partial caries removal with the application of CH, RMGIC, or gutta percha (control) and were then sealed for three months. After a partial caries removal and sealing period, the dentin was macroscopically assessed (for color, consistency, and humidity) and further analyzed by scanning electron microscope to assess the ultrastructural changes in dentin (lumen size, mineralization of tubules, occlusion of tubules by cements, and bacterial ingress). The effect of treatment in each group was statistically analyzed. Dentin darkening and hardening were observed after the sealing period in all groups. However, there was no difference in the color after treatment among the three groups. It was observed that RMGIC showed a significant reduction in the size of the lumen compared to CH and the control. Partial caries removal and sealing resulted in dentin hardening, darkening, and dentin remineralization, irrespective of the dentin protection used.

Pulp response to high fluoride releasing glass ionomer, silver diamine fluoride, and calcium hydroxide used for indirect pulp treatment: An in-vivo comparative study

PubMed Central

Korwar, Atish; Sharma, Sidhartha; Logani, Ajay; Shah, Naseem

2015-01-01

Aims and Objectives: The study aims at determining pulp response of two high fluoride releasing materials silver diamine fluoride (SDF) and Type VII glass ionomer cement (GIC) when used as indirect pulp treatment (IPT) materials. Materials and Methods: Deep Class V cavities were made on four first premolars indicated for extraction for orthodontic reasons. SDF, Type VII GIC, and calcium hydroxide base are given in three premolars, and one is kept control. Premolars were extracted 6 weeks after the procedure and subjected to histopathological examination to determine the pulp response. The results were analyzed using Chi-square test. Results: No inflammatory changes were observed in any of the groups. Significantly more number of specimens in SDF and Type VII GIC groups showed tertiary dentin deposition (TDD) when compared to control group. No significant difference was seen in TDD when intergroup comparison was made. Odontoblasts were seen as short cuboidal cells with dense basophilic nucleus in SDF and Type VII GIC group. Conclusion: The study demonstrated TDD inducing ability of SDF and Type VII GIC and also established the biocompatibility when used as IPT materials. PMID:26321822

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Magnesium hydroxide. 582.1428 Section 582.1428 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1428 Magnesium hydroxide. (a) Product. Magnesium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

21 CFR 582.1631 - Potassium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Potassium hydroxide. 582.1631 Section 582.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1631 Potassium hydroxide. (a) Product. Potassium hydroxide. (b) Conditions of use. This...

Calcium ion binding to a soil fulvic acid using a donnan potential model

USGS Publications Warehouse

Marinsky, J.A.; Mathuthu, A.; Ephraim, J.H.; Reddy, M.M.

1999-01-01

Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 X 10-4 moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log ??app) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log ??app = 2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential corrrection term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log??= 1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. ?? by Oldenbourg Wissenschaftsverlag, Mu??nchen.

Electrochemical formation of hydroxide for enhancing carbon dioxide and acid gas uptake by a solution

DOEpatents

Rau, Gregory Hudson [Castro Valley, CA

2012-05-15

A system is described for forming metal hydroxide from a metal carbonate utilizing a water electrolysis cell having an acid-producing anode and a hydroxyl-producing cathode immersed in a water solution of sufficient ionic content to allow an electric current to pass between the hydroxyl-producing cathode and the acid-producing anode. A metal carbonate, in particular water-insoluble calcium carbonate or magnesium carbonate, is placed in close proximity to the acid-producing anode. A direct current electrical voltage is provided across the acid-producing anode and the hydroxyl-producing cathode sufficient to generate acid at the acid-producing anode and hydroxyl ions at the hydroxyl-producing cathode. The acid dissolves at least part of the metal carbonate into metal and carbonate ions allowing the metal ions to travel toward the hydroxyl-producing cathode and to combine with the hydroxyl ions to form the metal hydroxide. The carbonate ions travel toward the acid-producing anode and form carbonic acid and/or water and carbon dioxide. Among other uses, the metal hydroxide formed can be employed to absorb acid gases such as carbon dioxide from a gas mixture. The invention can also generate hydrogen and oxidative gases such as oxygen or chlorine.

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... salt or by hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Magnesium hydroxide. 184.1428 Section 184.1428... Listing of Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

21 CFR 582.1763 - Sodium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Sodium hydroxide. 582.1763 Section 582.1763 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additives § 582.1763 Sodium hydroxide. (a) Product. Sodium hydroxide. (b) Conditions of use. This substance...

Evaluation of the Chemical and Mechanical Properties of Hardening High-Calcium Fly Ash Blended Concrete

PubMed Central

Fan, Wei-Jie; Wang, Xiao-Yong; Park, Ki-Bong

2015-01-01

High-calcium fly ash (FH) is the combustion residue from electric power plants burning lignite or sub-bituminous coal. As a mineral admixture, FH can be used to produce high-strength concrete and high-performance concrete. The development of chemical and mechanical properties is a crucial factor for appropriately using FH in the concrete industry. To achieve sustainable development in the concrete industry, this paper presents a theoretical model to systematically evaluate the property developments of FH blended concrete. The proposed model analyzes the cement hydration, the reaction of free CaO in FH, and the reaction of phases in FH other than free CaO. The mutual interactions among cement hydration, the reaction of free CaO in FH, and the reaction of other phases in FH are also considered through the calcium hydroxide contents and the capillary water contents. Using the hydration degree of cement, the reaction degree of free CaO in FH, and the reaction degree of other phases in FH, the proposed model evaluates the calcium hydroxide contents, the reaction degree of FH, chemically bound water, porosity, and the compressive strength of hardening concrete with different water to binder ratios and FH replacement ratios. The evaluated results are compared to experimental results, and good consistencies are found. PMID:28793543

21 CFR 184.1428 - Magnesium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... hydration of reactive grades of magnesium oxide. (b) The ingredient meets the specifications of the Food... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Magnesium hydroxide. 184.1428 Section 184.1428 Food... Specific Substances Affirmed as GRAS § 184.1428 Magnesium hydroxide. (a) Magnesium hydroxide (Mg(OH)2, CAS...

Optimization of Adhesive Pastes for Dental Caries Prevention.

PubMed

Sodata, Patteera; Juntavee, Apa; Juntavee, Niwut; Peerapattana, Jomjai

2017-11-01

Dental caries prevention products available on the market contain only remineralizing agents or antibacterial agents. This study aimed to develop adhesive pastes containing calcium phosphate and α-mangostin for dental caries prevention using the optimization technique. Calcium phosphate was used as a remineralizing agent, and extracted α-mangostin was used as an antibacterial agent. The effect of the independent variables, which were fumed silica, Eudragit ® EPO, polyethylene glycol, and ethyl alcohol, on the responses was investigated. The drying time, erosion rate, calcium release rate, and α-mangostin release rate were established as the measured responses. An equation and a model of the relationship were constructed. An optimal formulation was obtained, and its effect on dental caries prevention was investigated using the pH-cycling model. The quadratic equation revealed that the drying time, calcium release rate, and α-mangostin release rate tended to decrease when increasing the fumed silica and decreasing other factors. The erosion rate tended to increase when decreasing Eudragit ® EPO and increasing other factors. The observed responses of the optimal adhesive pastes were not significantly different from the predicted responses. This result demonstrated that optimization is an efficient technique in the formulation development of the adhesive pastes. In addition, the optimal adhesive pastes could enhance acid resistance activity to the tooth enamel.

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... Specific Substances Affirmed as GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The...

21 CFR 184.1763 - Sodium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium hydroxide. 184.1763 Section 184.1763 Food... GRAS § 184.1763 Sodium hydroxide. (a) Sodium hydroxide (NaOH, CAS Reg. No. 1310-73-2) is also known as sodium hydrate, soda lye, caustic soda, white caustic, and lye. The empirical formula is NaOH. Sodium...

Synthesis of spherical calcium phosphate particles for dental and orthopedic applications

PubMed Central

Bohner, Marc; Tadier, Solène; van Garderen, Noémie; de Gasparo, Alex; Döbelin, Nicola; Baroud, Gamal

2013-01-01

Calcium phosphate materials have been used increasingly in the past 40 years as bone graft substitutes in the dental and orthopedic fields. Accordingly, numerous fabrication methods have been proposed and used. However, the controlled production of spherical calcium phosphate particles remains a challenge. Since such particles are essential for the synthesis of pastes and cements delivered into the host bone by minimally-invasive approaches, the aim of the present document is to review their synthesis and applications. For that purpose, production methods were classified according to the used reagents (solutions, slurries, pastes, powders), dispersion media (gas, liquid, solid), dispersion tools (nozzle, propeller, sieve, mold), particle diameters of the end product (from 10 nm to 10 mm), and calcium phosphate phases. Low-temperature calcium phosphates such as monetite, brushite or octacalcium phosphate, as well as high-temperature calcium phosphates, such as hydroxyapatite, β-tricalcium phosphate or tetracalcium phosphate, were considered. More than a dozen production methods and over hundred scientific publications were discussed. PMID:23719177

Properties of calcium silicate-monobasic calcium phosphate materials for endodontics containing tantalum pentoxide and zirconium oxide.

PubMed

Zamparini, Fausto; Siboni, Francesco; Prati, Carlo; Taddei, Paola; Gandolfi, Maria Giovanna

2018-05-08

The aim of the study was to evaluate chemical-physical properties and apatite-forming ability of three premixed calcium silicate materials containing monobasic calcium phosphate (CaH 4 P 2 O 8 ) bioceramic, tantalum pentoxide and zirconium oxide, recently marketed for endodontics (TotalFill BC-Sealer, BC-RRM-Paste, BC-RRM-Putty). Microchemical and micromorphological analyses, radiopacity, initial and final setting times, calcium release and alkalising activity were tested. The nucleation of calcium phosphates (CaPs) and/or apatite after 28 days ageing was evaluated by ESEM-EDX and micro-Raman spectroscopy. BC-Sealer and BC-RRM-Paste showed similar initial (23 h), prolonged final (52 h) setting times and good radiopacity (> 7 mm Al); BC-RRM-Putty showed fast initial (2 h) and final setting times (27 h) and excellent radiopacity (> 9 mm Al). All materials induced a marked alkalisation (pH 11-12) up to 28 days and showed the release of calcium ions throughout the entire test period (cumulative calcium release 641-806 ppm). After 28 days ageing, a well-distributed mineral layer was present on all samples surface; EDX demonstrated relevant calcium and phosphorous peaks. B-type carbonated apatite and calcite deposits were identified by micro-Raman spectroscopy on all the 28-day-aged samples; the deposit thickness was higher on BC-RRM-Paste and BC-RRM-Putty, in agreement with calcium release data. These materials met the required chemical and physical standards and released biologically relevant ions. The CaSi-CaH 4 P 2 O 8 system present in the materials provided Ca and OH ions release with marked abilities to nucleate a layer of B-type carbonated apatite favoured/accelerated by the bioceramic presence. The ability to nucleate apatite may lead many clinical advantages: In orthograde endodontics, it may improve the sealing ability by the deposition of CaPs at the material-root dentine interface, and in endodontic surgery, it could promote bone and

The efficacy of the self-adjusting file and ProTaper for removal of calcium hydroxide from root canals

PubMed Central

FARIA, Gisele; KUGA, Milton Carlos; RUY, Alessandra Camila; ARANDA-GARCIA, Arturo Javier; BONETTI-FILHO, Idomeo; GUERREIRO-TANOMARU, Juliane Maria; LEONARDO, Renato Toledo

2013-01-01

Objective The goal of this study was to evaluate the efficacy of the Self-Adjusting File (SAF) and ProTaper for removing calcium hydroxide [Ca(OH)2] from root canals. Material and Methods Thirty-six human mandibular incisors were instrumented with the ProTaper system up to instrument F2 and filled with a Ca(OH)2-based dressing. After 7 days, specimens were distributed in two groups (n=15) according to the method of Ca(OH)2 removal. Group I (SAF) was irrigated with 5 mL of NaOCl and SAF was used for 30 seconds under constant irrigation with 5 mL of NaOCl using the Vatea irrigation device, followed by irrigation with 3 mL of EDTA and 5 mL of NaOCl. Group II (ProTaper) was irrigated with 5 mL of NaOCl, the F2 instrument was used for 30 seconds, followed by irrigation with 5 mL of NaOCl, 3 mL of EDTA, and 5 mL of NaOCl. In 3 teeth Ca(OH)2 was not removed (positive control) and in 3 teeth canals were not filled with Ca(OH)2 (negative control). Teeth were sectioned and prepared for the scanning electron microscopy. The amounts of residual Ca(OH)2 were evaluated in the middle and apical thirds using a 5-score system. Results None of the techniques completely removed the Ca(OH)2 dressing. No difference was observed between SAF and ProTaper in removing Ca(OH)2 in the middle (P=0.11) and the apical (P=0.23) thirds. Conclusion The SAF system showed similar efficacy to rotary instrument for removal of Ca(OH)2 from mandibular incisor root canals. PMID:24037074

Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.

PubMed

Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

2012-08-28

We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide.

Dissolution mechanism of aluminum hydroxides in acid media

NASA Astrophysics Data System (ADS)

Lainer, Yu. A.; Gorichev, I. G.; Tuzhilin, A. S.; Gololobova, E. G.

2008-08-01

The effects of the concentration, temperature, and potential at the hydroxide/electrolyte interface on the aluminum hydroxide dissolution in sulfuric, hydrochloric, and perchloric acids are studied. The limiting stage of the aluminum hydroxide dissolution in the acids is found to be the transition of the complexes that form on the aluminum hydroxide surface from the solid phase into the solution. The results of the calculation of the acid-base equilibrium constants at the oxide (hydroxide)/solution interface using the experimental data on the potentiometric titration of Al2O3 and AlOOH suspensions are analyzed. A mechanism is proposed for the dissolution of aluminum hydroxides in acid media.

Layered zinc hydroxide salts: delamination, preferred orientation of hydroxide lamellae, and formation of ZnO nanodiscs.

PubMed

Demel, Jan; Pleštil, Josef; Bezdička, Petr; Janda, Pavel; Klementová, Mariana; Lang, Kamil

2011-08-15

Delamination of layered zinc hydroxide salts (LZH) into hydroxide layers provides nanobuilding blocs of a two-dimensional anisotropy. The methodology, extent of delamination, the size and stability of hydroxide lamellae are described in detail. The ability of lamellae to restack to form oriented hydroxide films depends on the solvent, original LZH salt, and conditions used for delamination. The most interesting results were obtained using LZH intercalated with dodecyl sulfate anions and LZH nitrate delaminated in butanol at 60 °C and in formamide at room temperature, respectively. The former method produces hydroxide lamellae of a lateral size of ca. 10-20 nm. The inner structure of the hydroxide layers is conserved and separated lamellae restack to the original layered structure of LZH dodecyl sulfate. The latter method yields lamellae with a size decreasing from 73.3 nm to 10 nm after a 2-week aging, while their thickness is nearly constant (2.6-3.8 nm). However, the use of formamide is complicated by the formation of Zn(II) formate. The major part of LZH intercalated with dodecyl sulfate anions is transformed during the delamination procedure to anisotropic ZnO nanoparticles, either needle-like particles prolonged in the [0 0 1] direction or disc-like particles flattened along the (0 0 1) plane. Copyright © 2011 Elsevier Inc. All rights reserved.

40 CFR 721.4600 - Recovered metal hydroxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Recovered metal hydroxide. 721.4600... Substances § 721.4600 Recovered metal hydroxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a recovered metal hydroxide (PMN P-91-809...

Study of a hydraulic dicalcium phosphate dihydrate/calcium oxide-based cement for dental applications.

PubMed

el-Briak, Hasna; Durand, Denis; Nurit, Josiane; Munier, Sylvie; Pauvert, Bernard; Boudeville, Phillipe

2002-01-01

By mixing CaHPO(4) x 2H(2)O (DCPD) and CaO with water or sodium phosphate buffers as liquid phase, a calcium phosphate cement was obtained. Its physical and mechanical properties, such as compressive strength, initial and final setting times, cohesion time, dough time, swelling time, dimensional and thermal behavior, and injectability were investigated by varying different parameters such as liquid to powder (L/P) ratio (0.35-0.7 ml g(-1)), molar calcium to phosphate (Ca/P) ratio (1.67-2.5) and the pH (4, 7, and 9) and the concentration (0-1 M) of the sodium phosphate buffer. The best results were obtained with the pH 7 sodium phosphate buffer at the concentration of 0.75 M. With this liquid phase, physical and mechanical properties depended on the Ca/P and L/P ratios, varying from 3 to 11 MPa (compressive strength), 6 to 10 min (initial setting time), 11 to 15 min (final setting time), 15 to 30 min (swelling time), 7 to 20 min (time of 100% injectability). The dough or working time was over 16 min. This cement expanded during its setting (1.2-5 % according to Ca/P and L/P ratios); this would allow a tight filling. Given the mechanical and rheological properties of this new DCPD/CaO-based cement, its use as root canal sealing material can be considered as classical calcium hydroxide or ZnO/eugenol-based pastes, without or with a gutta-percha point. Copyright 2002 Wiley Periodicals, Inc. J Biomed Mater Res (Appl Biomater) 63: 447-453, 2002

On the Nickel Hydroxide Electrode. I. On Nickel (II) Hydroxide Hydrate,

DTIC Science & Technology

1980-10-27

1 - 4.60 A), and the hydrous form is halloysite , AI 2Si2 O5 (OH)4 .2H20 with d001 - 10.25 A (analogous to a-3Ni(OH)2 .2H20 with do01 - 8.07 A). On...heating of halloysite , the entire intermediate layer water is lost at about 1500 C, as for a nickel hydroxide, without the hydroxide layer separation...significantly reducing to meta- halloysite . 13 The conversion of the a form under the influence of alkali goes only in one direction. This monotropic

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2010 CFR

2010-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O). (2) Color additive mixtures for drug use made with chromium hydroxide green may contain only those...

Effect of alkali and oxidative treatments on the physicochemical, pasting, thermal and morphological properties of corn starch.

PubMed

Spier, Franciela; Zavareze, Elessandra da Rosa; Marques e Silva, Ricardo; Elias, Moacir Cardoso; Dias, Alvaro Renato Guerra

2013-07-01

Few studies on starch modifications using different chemical agents are available in the literature, and no reports were found on the combined effect of oxidation and alkaline treatment of corn starch. Thus this work evaluated the physicochemical, pasting, morphological, cystallinity and thermal properties of chemically modified corn starch, after either the isolated or combined action of alkaline (sodium hydroxide) and oxidative (sodium hypochlorite) treatments. The highest values for the sum of carbonyl and carboxyl and enzymatic hydrolysis occurred in starches submitted to oxidative treatment at high active chlorine concentrations. The alkali treatment in isolation modified the pasting properties, reduced the paste temperature and increased the peak viscosity, breakdown, final viscosity and setback of starches. Starch modified by the action of sodium hypochlorite and hydroxide in combination presented more severe damage on granule surfaces. The results show that corn starch modified by the combined action of oxidative and alkaline treatments should be studied more, especially at the concentration limit of sodium hydroxide where gelatinization occurs. Under these conditions the effect of oxidation can be more intense and thus allow the production of starches with different properties and an increase in their industrial applications. © 2013 Society of Chemical Industry.

Antibacterial effect of calcium hydroxide combined with chlorhexidine on Enterococcus faecalis: a systematic review and meta-analysis

PubMed Central

SAATCHI, Masoud; SHOKRANEH, Ali; NAVAEI, Hooman; MARACY, Mohammad Reza; SHOJAEI, Hasan

2014-01-01

Objective Enterococcus faecalis (E. faecalis) is the most frequently isolated strain in failed endodontic therapy cases since it is resistant to calcium hydroxide (CH). Whether a combination of CH and chlorhexidine (CHX) is more effective than CH alone against E. faecalis is a matter of controversy. Thus, the aim of this study was to conduct a systematic review and meta-analysis of the literature. Material and Methods A comprehensive search in PubMed, EMbase, EBSCOhost, The Cochrane Library, SciELO, and BBO databases, Clinical trials registers, Open Grey, and conference proceedings from the earliest available date to February 1, 2013 was carried out and the relevant articles were identified by two independent reviewers. Backward and forward search was performed and then inclusion and exclusion criteria were applied. The included studies were divided into "comparisons" according to the depth of sampling and dressing period of each medicament. Meta-analysis was performed using Stata software 10.0. The level of significance was set at 0.05. Results Eighty-five studies were retrieved from databases and backward/forward searches. Fortyfive studies were considered as relevant (5 in vivo, 18 in vitro, 18 ex vivo, and 4 review articles). Nine studies were included for meta-analysis. Inter-observer agreement (Cohen kappa) was 0.93. The included studies were divided into 21 comparisons for meta-analysis. Chi-square test showed the comparisons were heterogeneous (p<0.001). Random effect model demonstrated no significant difference between CH/CHX mixture and CH alone in their effect on E. faecalis (p=0.115). Conclusions According to the evidence available now, mixing CH with CHX does not significantly increase the antimicrobial activity of CH against E. faecalis. It appears that mixing CH with CHX does not improve its ex vivo antibacterial property as an intracanal medicament against E. faecalis. Further in vivo studies are necessary to confirm and correlate the findings of

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2012 CFR

2012-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

21 CFR 582.1139 - Ammonium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Additives § 582.1139 Ammonium hydroxide. (a) Product. Ammonium hydroxide. (b) Conditions of use. This substance is generally recognized as safe when used in accordance with good manufacturing or feeding...

Biopharmaceutical characterisation of ciprofloxacin-metallic ion interactions: comparative study into the effect of aluminium, calcium, zinc and iron on drug solubility and dissolution.

PubMed

Stojković, Aleksandra; Tajber, Lidia; Paluch, Krzysztof J; Djurić, Zorica; Parojčić, Jelena; Corrigan, Owen I

2014-03-01

Ciprofloxacin bioavailability may be reduced when ciprofloxacin is co-administered with metallic ion containing preparations. In our previous study, physicochemical interaction between ciprofloxacin and ferrous sulphate was successfully simulated in vitro. In the present work, comparative in vitro ciprofloxacin solubility and dissolution studies were performed in the reactive media containing aluminium hydroxide, calcium carbonate or zinc sulphate. Solid phases collected from the dissolution vessel with aluminium hydroxide, calcium carbonate and zinc sulphate were investigated for their properties. The results obtained indicate that different types of adducts may form and retard ciprofloxacin solubility and dissolution. In the case of aluminium, no phase changes were observed. The solid phase generated in the presence of calcium carbonate was identified as hydrated ciprofloxacin base. Similarly to iron, a new complex consistent with Zn(SO4)2(Cl)2(ciprofloxacin)2 × nH2O stoichiometry was generated in the presence of relatively high concentrations of ciprofloxacin hydrochloride and zinc sulphate, indicating that small volume dissolution experiments can be useful for biorelevant dissolution tests.

Pretreatment of rapeseed straw by sodium hydroxide.

PubMed

Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

2012-06-01

Pretreatment method for rapeseed straw by sodium hydroxide was investigated for production of bioethanol and biobutanol. Various pretreatment parameters, including temperature, time, and sodium hydroxide concentration were optimized using a statistical method which is a central composite design of response surface methodology. In the case of sodium hydroxide pretreatment, optimal pretreatment conditions were found to be 7.9% sodium hydroxide concentration, 5.5 h of reaction time, and 68.4 °C of reaction temperature. The maximum glucose yield which can be recovered by enzymatic hydrolysis at the optimum conditions was 95.7% and the experimental result was 94.0 ± 4.8%. This experimental result was in agreement with the model prediction. An increase of surface area and pore size in pretreated rapeseed straw by sodium hydroxide pretreatment was observed by scanning electron microscope.

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1) The color additive chromium hydroxide green is principally hydrated chromic sesquioxide (Cr2O3·XH2O...

SEM Analysis of the Interfacial Transition Zone between Cement-Glass Powder Paste and Aggregate of Mortar under Microwave Curing

PubMed Central

Kong, Yaning; Wang, Peiming; Liu, Shuhua; Zhao, Guorong; Peng, Yu

2016-01-01

In order to investigate the effects of microwave curing on the microstructure of the interfacial transition zone of mortar prepared with a composite binder containing glass powder and to explain the mechanism of microwave curing on the improvement of compressive strength, in this study, the compressive strength of mortar under microwave curing was compared against mortar cured using (a) normal curing at 20 ± 1 °C with relative humidity (RH) > 90%; (b) steam curing at 40 °C for 10 h; and (c) steam curing at 80 °C for 4 h. The microstructure of the interfacial transition zone of mortar under the four curing regimes was analyzed by Scanning electron microscopy (SEM). The results showed that the improvement of the compressive strength of mortar under microwave curing can be attributed to the amelioration of the microstructure of the interfacial transition zone. The hydration degree of cement is accelerated by the thermal effect of microwave curing and Na+ partially dissolved from the fine glass powder to form more reticular calcium silicate hydrate, which connects the aggregate, calcium hydroxide, and non-hydrated cement and glass powder into a denser integral structure. In addition, a more stable triangular structure of calcium hydroxide contributes to the improvement of compressive strength. PMID:28773854

SEM Analysis of the Interfacial Transition Zone between Cement-Glass Powder Paste and Aggregate of Mortar under Microwave Curing.

PubMed

Kong, Yaning; Wang, Peiming; Liu, Shuhua; Zhao, Guorong; Peng, Yu

2016-08-27

In order to investigate the effects of microwave curing on the microstructure of the interfacial transition zone of mortar prepared with a composite binder containing glass powder and to explain the mechanism of microwave curing on the improvement of compressive strength, in this study, the compressive strength of mortar under microwave curing was compared against mortar cured using (a) normal curing at 20 ± 1 °C with relative humidity (RH) > 90%; (b) steam curing at 40 °C for 10 h; and (c) steam curing at 80 °C for 4 h. The microstructure of the interfacial transition zone of mortar under the four curing regimes was analyzed by Scanning electron microscopy (SEM). The results showed that the improvement of the compressive strength of mortar under microwave curing can be attributed to the amelioration of the microstructure of the interfacial transition zone. The hydration degree of cement is accelerated by the thermal effect of microwave curing and Na⁺ partially dissolved from the fine glass powder to form more reticular calcium silicate hydrate, which connects the aggregate, calcium hydroxide, and non-hydrated cement and glass powder into a denser integral structure. In addition, a more stable triangular structure of calcium hydroxide contributes to the improvement of compressive strength.

Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

NASA Astrophysics Data System (ADS)

Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

2017-07-01

Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

Fracture resistance of immature teeth filled with BioAggregate, mineral trioxide aggregate and calcium hydroxide.

PubMed

Tuna, Elif Bahar; Dinçol, Muzaffer Emir; Gençay, Koray; Aktören, Oya

2011-06-01

Abstract -  Background: The aim of this in vitro study was to assess the long-term fracture resistance of human immature permanent teeth filled with BioAggregate (BA), mineral trioxide aggregate (MTA) and calcium hydroxide (CH).  The study consisted of single rooted premolar teeth with immature root formation extracted for orthodontic reasons. A total of 28 immature premolars with average root length of 10.7 mm and apical diameter of 3 mm were included in the study. The pulps were extirpated and the canals were prepared using an apical approach. The teeth were randomly assigned to four groups: Group I: DiaRoot(®) BA (DiaDent, Burnaby, BC, Canada), Group II: Angelus MTA (MTA-A; Angelus, Londrina, Brazil), Group III: ProRoot(®) MTA (MTA-PR; Dentsply, Tulsa, OK, USA), Group IV: CH (Sultan Chemists Inc., Englewood, NJ, USA). The teeth were placed in saline solution at 4°C for 1 year. The root of each tooth was then embedded in an acrylic resin block. All specimens were loaded at a crosshead speed of 1 mm min(-1) in an Instron testing machine and the peak loads up to fracture were recorded. Data were analysed statistically by Kruskal-Wallis and Mann-Whitney U-tests.  Mean (±SD) failure loads (MPa) were: 37.69 ± 14.43 for BA group, 32.94 ± 8.15 for MTA-A group, 28.74 ± 9.49 for MTA-PR group and 23.18 ± 8.48 for CH group. The BA group exhibited the highest fracture resistance and the CH group showed the lowest resistance to fracture. Significant differences (P < 0.05) in fracture resistance were found between the DiaRoot-BA and CH groups, and also between the MTA-A and CH groups.  Within the limitations of this study, data suggest that DiaRoot-BA-filled immature teeth demonstrate higher fracture resistance than other groups at 1 year. Considering the long-term risk of cervical root fracture associated with immature teeth, the use of DiaRoot-BA as a root canal filling material appears to be the most advantageous of the

Management of Cyst-like Periapical Lesions by Orthograde Decompression and Long-term Calcium Hydroxide/Chlorhexidine Intracanal Dressing: A Case Series.

PubMed

Santos Soares, Suelleng Maria Cunha; Brito-Júnior, Manoel; de Souza, Flávia Kelly; Zastrow, Eduardo Von; Cunha, Carla Oliveira da; Silveira, Frank Ferreira; Nunes, Eduardo; César, Carlos Augusto Santos; Glória, José Cristiano Ramos; Soares, Janir Alves

2016-07-01

Cyst-like periapical lesions should be treated initially with conservative nonsurgical procedures. In this case series, we describe the clinical and radiographic outcomes of large cyst-like lesions that were treated by orthograde decompression and long-term intracanal use of calcium hydroxide [Ca(OH)2] mixed with 2% chlorhexidine digluconate. Ten cases of cyst-like periapical lesions involving 15 teeth from 10 patients were selected. Maximal radiographic diameters of the lesions ranged from 11 to 28 mm. Nonsurgical procedures were performed, including apical patency, orthograde puncture of cyst-like exudates, chemomechanical preparation, and placement of intracanal Ca(OH)2/CHX dressings, which were periodically replaced during 6-10 months. The root canals were then filled with gutta-percha and sealer. The follow-up periods ranged from 6 to 24 months, and the outcome was classified as healed, healing, or failure. Nine lesions drained copious exudates after canal patency. One lesion only drained bloody serous exudate after periapical overinstrumentation. In 9 patients, intracanal exudation ceased in the first follow-up visit. At the 24-month follow-up, 6 lesions (60.0%) had healed, and 3 lesions (30.0%) were healing, with the corresponding patients being without clinical signs or symptoms. The case of treatment failure was submitted to surgical treatment. Microscopically, the lesion appeared to be an apical cyst with exuberant extraradicular bacterial biofilms attached to the sectioned root apex. This case series supports the use of nonsurgical methods to resolve larger cyst-like periapical lesions. Published by Elsevier Inc.

Pulp Revascularization: A Literature Review

PubMed Central

Araújo, Pollyana Rodrigues de Souza; Silva, Luciano Barreto; Neto, Alexandrino Pereira dos Santos; Almeida de Arruda, José Alcides; Álvares, Pâmella Recco; Sobral, Ana Paula Veras; Júnior, Severino Alves; Leão, Jair Carneiro; Braz da Silva, Rodivan; Sampaio, Gerhilde Callou

2017-01-01

Reestablishing blood flow and allowing the continuation of root development are some of the objectives of pulp revascularization. This procedure is currently indicated for teeth with incomplete root formation as an alternative to the traditional treatment of apecification, which consists of inserting calcium hydroxide paste into the root canal for a determined time period in order to induce the formation of a calcified barrier. Although it is considered as the most classically employed therapy, the permanence of the paste for long time periods may lead to the weakening of the root due to hygroscopic properties, as well as proteolytic activities of calcium hydroxide. Therefore, there has been a permanent search for alternatives which allow the full development of immature teeth. Revascularization has emerged as such an alternative, and a range of treatment protocols can be found in the scientific literature. The aim of this paper is to accomplish a literature review concerning this issue. PMID:28567136

A Systematic Review of Root Canal Filling Materials for Deciduous Teeth: Is There an Alternative for Zinc Oxide-Eugenol?

PubMed Central

Barja-Fidalgo, Fernanda; Moutinho-Ribeiro, Michele; Oliveira, Maria Angelina Amorim; de Oliveira, Branca Heloísa

2011-01-01

The aim of this systematic review was to determine whether there is a root canal filling for deciduous teeth equally or more effective than zinc oxide-eugenol cement (ZOE). Six clinical trials selected for inclusion were independently reviewed by two researchers. Only two showed statistically significant different success rates between the test and the control groups. One found that an iodoform paste with calcium hydroxide (IP + Ca) performed better than ZOE, and the other found that ZOE performed similarly to IP + Ca. The other four studies compared ZOE with an iodoform paste (IP), a calcium hydroxide cement (Ca(OH)2), or IP + Ca. In these trials, the success rates in the ZOE groups were slightly lower than in the other groups. There seems to be no convincing evidence to support the superiority of any material over ZOE, and both ZOE and IP + Ca appear to be suitable as root canal fillings for deciduous teeth. PMID:21991471

Layered double hydroxide stability. 1. Relative stabilities of layered double hydroxides and their simple counterparts

NASA Technical Reports Server (NTRS)

Boclair, J. W.; Braterman, P. S.

1999-01-01

Solutions containing di- and trivalent metal chlorides [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+; M(III) = Al3+, Fe3+] were titrated with NaOH to yield hydrotalcite-like layered double hydroxides (LDH), [[M(II)]1-x[M(III)]x(OH)2][Cl]x yH2O, by way of M(III) hydroxide/hydrous oxide intermediates. Analysis of the resultant titration curves yields nominal solubility constants for the LDH. The corresponding LDH stabilities are in the order Mg < Mn < Co approximately Ni < Zn for M(II) and Al < Fe for M(III). The stability of LDH relative to the separate metal hydroxides/hydrous oxides is discussed.

Kinetics and Mechanism of Calcium Hydroxide Conversion into Calcium Alkoxides: Implications in Heritage Conservation Using Nanolimes.

PubMed

Rodriguez-Navarro, Carlos; Vettori, Irene; Ruiz-Agudo, Encarnacion

2016-05-24

Nanolimes are alcohol dispersions of Ca(OH)2 nanoparticles used in the conservation of cultural heritage. Although it was believed that Ca(OH)2 particles were inert when dispersed in short-chain alcohols, it has been recently shown that they can undergo transformation into calcium alkoxides. Little is known, however, about the mechanism and kinetics of such a phase transformation as well as its effect on the performance of nanolimes. Here we show that Ca(OH)2 particles formed after lime slaking react with ethanol and isopropanol and partially transform (fractional conversion, α up to 0.08) into calcium ethoxide and isopropoxide, respectively. The transformation shows Arrhenius behavior, with apparent activation energy Ea of 29 ± 4 and 37 ± 6 kJ mol(-1) for Ca-ethoxide and Ca-isopropoxide conversion, respectively. High resolution transmission electron microscopy analyses of reactant and product phases show that the alkoxides replace the crystalline structure of Ca(OH)2 along specific [hkl] directions, preserving the external hexagonal (platelike) morphology of the parent phase. Textural and kinetic results reveal that this pseudomorphic replacement involves a 3D diffusion-controlled deceleratory advancement of the reaction front. The results are consistent with an interface-coupled dissolution-precipitation replacement mechanism. Analysis of the carbonation of Ca(OH)2 particles with different degree of conversion into Ca-ethoxide (α up to 0.08) and Ca-isopropoxide (α up to 0.04) exposed to air (20 °C, 80% relative humidity) reveals that Ca-alkoxides significantly reduce the rate of transformation into cementing CaCO3 and induce the formation of metastable vaterite, as opposed to stable calcite which forms in untransformed Ca(OH)2 samples. Similar effects are obtained when a commercial nanolime partially transformed into Ca-ethoxide is subjected to carbonation. Such effects may hamper/delay the strengthening or consolidation effects of nanolimes, thus having

21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

Code of Federal Regulations, 2010 CFR

2010-04-01

... GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1010 Alumina (dried aluminum hydroxide). (a) Identity. (1) The color additive alumina (dried aluminum hydroxide) is a white, odorless, tasteless, amorphous powder consisting essentially of aluminum hydroxide (Al2 O3· XH2 O). (2) Color additive...

Hydroxide Solvation and Transport in Anion Exchange Membranes.

PubMed

Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E; Knight, Chris; Voth, Gregory A

2016-01-27

Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

Efficacy of Needle, Ultrasonic, and Endoactivator Irrigation and Photon-Induced Photoacoustic Streaming in Removing Calcium Hydroxide from the Main Canal and Isthmus: An In Vitro Micro-Computed Tomography and Scanning Electron Microscopy Study.

PubMed

Li, Dongxia; Jiang, Shan; Yin, Xingzhe; Chang, Jeffrey Wen Wei; Ke, Jie; Zhang, Chengfei

2015-06-01

The aim of this in vitro study was to use high-resolution micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) to compare the efficacy of four irrigation techniques [needle, ultrasonic, EndoActivator, and photon-induced photoacoustic streaming (PIPS)] in removing calcium hydroxide (Ca[OH]2) from the root canal and isthmus of maxillary premolars. Twenty-four maxillary first premolars were selected based on the presence of isthmus regions on micro-CT scans. Root canals were instrumented with an F2 file using ProTaper rotary instruments and filled with Ca(OH)2 paste. Samples were stored at 37°C and 100% humidity for 1 week and randomly divided into four groups (n=6 each), according to irrigation technique. Samples were scanned with micro-CT before instrumentation, after Ca(OH)2 filling, and after irrigation. Ca(OH)2 reduction in the coronal, middle, and apical thirds and in the isthmus were assessed with three-dimensional image analysis. Next, specimens were split longitudinally, and canal walls were examined with SEM for Ca(OH)2 residues. Data were statistically evaluated with the Kruskal-Wallis and Mann-Whitney tests (p=0.05). The PIPS and ultrasonic groups showed greater Ca(OH)2 reduction in the apical third and higher cleanliness of the isthmus than the EndoActivator and needle irrigation groups (p<0.05). Ca(OH)2 residue scores in the PIPS and ultrasonic groups were significantly lower than those in the EndoActivator and needle groups in all regions of the root canals (p<0.05). There was no significant difference between PIPS and ultrasonic groups (p>0.05), or between EndoActivator and needle groups (p>0.05). PIPS and ultrasonic irrigation more effectively removed Ca(OH)2 from the main canal and isthmus in maxillary premolars than did EndoActivator or needle irrigation.

Synthesis and effectiveness of overbased magnesium and calcium petroleum sulfonates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fialkovskii, R.V.; Romanyutina, L.V.; Korbut, L.F.

Overbased sulfonate additives are widely used to improve the service properties of motor oils. This paper describes the preparation of an overbased magnesium sulfonate additive from MSG-8 oil and an investigation of its functional properties. In experiments, the solution of ammonium sulfate, fat diluted with I-20A oil to a 38% concentration, was heated and stirred continuously in the presence of water and excess magnesium oxide for a period of 4 h at 80-120/degree/C while stripping out the liberated ammonia with nitrogen. The resulting oil solution of magnesium sulfonate was dissolved in toluene. The toluene solution after cleanup was held undermore » vacuum to remove the solvent; the residue was an oil solution of overbased magnesium sulfonate. Their properties are tabulated. Comparative data are shown in Table 1 for a calcium sulfonate additive synthesized from the same intermediate (ammonium sulfate), using calcium hydroxide as the base. Test results on M-11 oil containing 5% of the magnesium or calcium additive are listed. It is shown that the magnesium additive gave better results from the calcium additive at the same concentration in terms of oxidation stability, corrosion properties, detergency, and dispersancy. 9 refs.« less

Time-dependent antibacterial effects of Aloe vera and Zataria multiflora plant essential oils compared to calcium hydroxide in teeth infected with Enterococcus faecalis.

PubMed

Abbaszadegan, Abbas; Sahebi, Safoora; Gholami, Ahmad; Delroba, Alireza; Kiani, Amin; Iraji, Aida; Abbott, Paul Vincent

2016-02-01

In the present in vitro study, we investigated the time-related antimicrobial efficacy of Aloe vera and Zataria multiflora (Z. multiflora) plant essential oils compared to calcium hydroxide ([Ca[OH]2 ) to eliminate Enterococcus faecalis (E. faecalis) from root canals. A new strain of E. faecalis (Enterococcus spp. AGH04) was isolated from a previously root-filled tooth with persistent apical periodontitis. The 16S rRNA sequence was analyzed and deposited in GeneBank under accession number KF465681. A total of 108 extracted human single-rooted teeth were contaminated with this bacterial strain and treated with Aloe vera essential oil, Z. multiflora essential oil, and Ca(OH)2 for 1, 7, and 14 days. Gas chromatography-mass spectrometry (GC-MS) was used to determine the chemical composition of the oils. The percentage reduction from initial c.f.u./mL counts were calculated and analyzed. Carvacrol, thymol, and linalool were the main constituents of both essential oils. The c.f.u./mL count reductions significantly increased for all three medicaments when the contact time was extended. A statistically-significant difference was observed between the medicaments after 1 and 7 days, but there was no significant difference after 14 days. Both medicinal herbs showed equal antimicrobial efficiency against E. faecalis, comparable to Ca(OH)2 for the prolonged contact time of 14 days. © 2014 Wiley Publishing Asia Pty Ltd.

Hydroxide Solvation and Transport in Anion Exchange Membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chen; Tse, Ying-Lung Steve; Lindberg, Gerrick E.

Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationicmore » groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.« less

Polymeric additives to enhance the functional properties of calcium phosphate cements

PubMed Central

Perez, Roman A; Kim, Hae-Won

2012-01-01

The vast majority of materials used in bone tissue engineering and regenerative medicine are based on calcium phosphates due to their similarity with the mineral phase of natural bone. Among them, calcium phosphate cements, which are composed of a powder and a liquid that are mixed to obtain a moldable paste, are widely used. These calcium phosphate cement pastes can be injected using minimally invasive surgery and adapt to the shape of the defect, resulting in an entangled network of calcium phosphate crystals. Adding an organic phase to the calcium phosphate cement formulation is a very powerful strategy to enhance some of the properties of these materials. Adding some water-soluble biocompatible polymers in the calcium phosphate cement liquid or powder phase improves physicochemical and mechanical properties, such as injectability, cohesion, and toughness. Moreover, adding specific polymers can enhance the biological response and the resorption rate of the material. The goal of this study is to overview the most relevant advances in this field, focusing on the different types of polymers that have been used to enhance specific calcium phosphate cement properties. PMID:22511991

Efficacy of sonic and ultrasonic activation for removal of calcium hydroxide from mesial canals of mandibular molars: a microtomographic study.

PubMed

Wiseman, Anne; Cox, Timothy C; Paranjpe, Avina; Flake, Natasha M; Cohenca, Nestor; Johnson, James D

2011-02-01

The purpose of this study was to use micro-computed tomography (micro-CT) scanning to evaluate the efficacy of sonic and passive ultrasonic irrigation (PUI) on calcium hydroxide (Ca[OH](2)) removal and to measure the volume and percentage of Ca(OH)(2) remaining in the root canal system. The root canals of 46 extracted human mandibular molar teeth were prepared with rotary instruments and randomly assigned to two experimental groups (n = 40) as well as positive and negative controls (n = 6). In each experimental group, 20 teeth were assigned to each irrigation protocol, sonic or passive ultrasonic irrigation. All experimental teeth and the positive controls were filled with Ca(OH)(2), whereas the negative control teeth did not receive Ca(OH)(2). All teeth were scanned using micro-CT scanning to determine the dressing volume. After 7 days, the Ca(OH)(2) was removed in the experimental groups using rotary instrumentation only, and the teeth were again scanned using micro-CT scanning to calculate volume and percentage of Ca(OH)(2) removed. Positive control teeth were not subjected to rotary instrumentation. Experimental samples were then irrigated using either sonic or passive ultrasonic and the volume of remaining Ca(OH)(2) was calculated using micro-CT. Remnants of Ca(OH)(2) were found in all experimental groups. No Ca(OH)(2) was found in the negative controls, whereas a mean of 8.7 mm(3) of Ca(OH)(2) was recorded in the positive controls. Rotary plus passive ultrasonic irrigation removed significantly more Ca(OH)(2) (85.7%) than rotary plus sonic irrigation (71.5%) (p < 0.001). The combination of rotary instrumentation and passive ultrasonic activation for 3 periods of 20 seconds results in significantly lower amounts of Ca(OH)(2) remnants in the canal compared with sonic irrigation. Copyright © 2011. Published by Elsevier Inc.

Calcium silicate-based sealers: Assessment of physicochemical properties, porosity and hydration.

PubMed

Marciano, Marina Angélica; Duarte, Marco Antonio Hungaro; Camilleri, Josette

2016-02-01

Investigation of hydration, chemical, physical properties and porosity of experimental calcium silicate-based sealers. Experimental calcium silicate-based sealers with calcium tungstate and zirconium oxide radio-opacifiers were prepared by mixing 1g of powder to 0.3 mL of 80% distilled water and 20% propylene glycol. MTA and MTA Fillapex were used as controls. The raw materials and set sealers were characterized using a combination of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. Physical properties were analyzed according to ANSI/ADA. The pH and calcium ion release were assessed after 3, 24, 72 and 168 h. The porosity was assessed using mercury intrusion porosimetry. The analysis of hydration of prototype sealers revealed calcium hydroxide as a by-product resulting in alkaline pH and detection of calcium ion release, with high values in initial periods. The radiopacity was similar to MTA for the sealers containing high amounts of radio-opacifiers (p>0.05). Flowability was higher and film thickness was lower for resinous MTA Fillapex sealer (p<0.05). The test sealers showed water sorption and porosity similar to MTA (p>0.05). The prototype sealers presented adequate hydration, elevated pH and calcium ion release. Regarding physical properties, elevated proportions of radio-opacifiers were necessary to accomplish adequate radiopacity, enhance flowability and reduce film thickness. All the tested sealers presented water sorption and porosity similar to MTA. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bortolaz de Oliveira, Henrique; Wypych, Fernando, E-mail: wypych@ufpr.br

Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO{sub 4}{sup 2−}/g of material, respectively. Although the removal values obtained for Zn/NiHN andmore » Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO{sub 4}{sup 2−}/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated. - Highlights: • Zinc hydroxide nitrate and Zn/Ni hydroxide nitrate or acetate were synthesized. • The interlayer anions were replaced by chromate anions at pH=8.0. • Only Zn/Ni hydroxide nitrate or acetate have the structure preserved after exchange. • Fast exchange reaction and high capacity of chromate removal were observed. • Magnetic materials were obtained to facilitate the solids removal the from solutions.« less

Effects of soaking and acidification on physicochemical properties of calcium-fortified rice.

PubMed

Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa

2016-06-01

Calcium-fortified rice was prepared by soaking milled rice in calcium lactate solution, steaming and drying, and physicochemical properties were determined to evaluate effects of calcium concentration (0, 30, 50 g L(-1) ), soaking temperature (ambient temperature, 40 °C, 60 °C) and acidification. Calcium-fortified rice had less lightness. More total solid loss was observed, especially at high soaking temperature. Harder texture was detected with increased calcium concentration. Calcium fortification lowered pasting viscosity of milled rice. Panelists accepted all fortified rice; however, only rice soaked at 50 g L(-1) concentration could be claimed as a good source of calcium. Increasing of soaking temperature induced more penetration of calcium to rice kernels but calcium was lost more easily after washing. With addition of acetic acid to the soaking solution, enriched calcium content was comparable to that of high soaking temperature but with better retention after washing and calcium solubility was improved. Acid induced reduction of lightness and cooked rice hardness but increased total solid loss and pasting viscosity. Although the taste of acetic acid remained, panelists still accepted the fortified rice. Calcium-fortified rice (190.47-194.3 mg 100 g(-1) ) could be successfully produced by soaking milled rice in 50 g L(-1) calcium lactate solution at 40 °C or at ambient temperature with acidification. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Evaluation of time required for recontamination of coronally sealed canals medicated with calcium hydroxide and chlorhexidine.

PubMed

Gomes, B P F A; Sato, E; Ferraz, C C R; Teixeira, F B; Zaia, A A; Souza-Filho, F J

2003-09-01

To determine in vitro the time required for recontamination of coronally sealed canals medicated with either calcium hydroxide (CaOH2), 2% chlorhexidine gel (CG) or with a combination of both. Eighty intact, caries-free, premolar teeth with straight roots and mature apices were selected for the study. After biomechanical preparation of 75 teeth, they were randomly divided into nine groups according to the intracanal medicament and the coronal seal with 'Intermediate Restorative Material' (IRM) as follows: (i) 10 teeth medicated with CG, coronally unsealed; (ii) 10 teeth medicated with CaOH2, coronally unsealed; (iii) 10 teeth medicated with CaOH2 + CG, coronally unsealed; (iv) 10 teeth medicated with CG + coronal seal; (v) 10 teeth medicated with CaOH2 + coronal seal; (vi) 10 teeth medicated with CG + CaOH2 + coronal seal; (vii) 10 teeth without intracanal medicament and coronally sealed; (viii) 5 teeth without intracanal medicament and coronally unsealed, used as the positive control group (PC); (ix) 5 teeth with intact crowns used as the negative control group (NC). Glass flasks were filled with Brain Heart Infusion broth (BHI), so that only the root apex was in contact with the broth, while the crown was immersed in human saliva + BHI (3:1). The flasks were then incubated at 37 degrees C in an atmosphere of 10% CO2, and microbial growth was checked daily. All specimens of the PC showed contamination within 1 day of incubation, while the NC showed no evidence of broth turbidity. Recontamination was detected after an average time of 3.7 days in the unsealed canals medicated with CG, 1.8 days in the group medicated with CaOH2 and 2.6 days in the group medicated with CaOH2 + CG. When the crowns were sealed with IRM, recontamination was detected within 13.5 days in the canals medicated with CG, after 17.2 days in the group medicated with CaOH2 and after 11.9 days in the group medicated with CG + CaOH2. The group with no medication, but sealed with IRM, showed

Potassium hydroxide poisoning

MedlinePlus

... effectively treat (adsorb) sodium hydroxide. For skin exposure, treatment may include: Surgical removal of burned skin (debridement) Transfer to a hospital that specializes in burn care Washing of the skin (irrigation), possibly every ...

40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

40 CFR 721.10504 - Surface modified magnesium hydroxide (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Surface modified magnesium hydroxide... Specific Chemical Substances § 721.10504 Surface modified magnesium hydroxide (generic). (a) Chemical... as surface modified magnesium hydroxide (PMN P-06-682) is subject to reporting under this section for...

Effect of chemical admixtures on properties of high-calcium fly ash geopolymer

NASA Astrophysics Data System (ADS)

Rattanasak, Ubolluk; Pankhet, Kanokwan; Chindaprasirt, Prinya

2011-06-01

Owing to the high viscosity of sodium silicate solution, fly ash geopolymer has the problems of low workability and rapid setting time. Therefore, the effect of chemical admixtures on the properties of fly ash geopolymer was studied to overcome the rapid set of the geopolymer in this paper. High-calcium fly ash and alkaline solution were used as starting materials to synthesize the geopolymer. Calcium chloride, calcium sulfate, sodium sulfate, and sucrose at dosages of 1wt% and 2wt% of fly ash were selected as admixtures based on concrete knowledge to improve the properties of the geopolymer. The setting time, compressive strength, and degree of reaction were recorded, and the microstructure was examined. The results show that calcium chloride significantly shortens both the initial and final setting times of the geopolymer paste. In addition, sucrose also delays the final setting time significantly. The degrees of reaction of fly ash in the geopolymer paste with the admixtures are all higher than those of the control paste. This contributes to the obvious increases in compressive strength.

Polysulfide intercalated layered double hydroxides for metal capture applications

DOEpatents

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

Effects of mineral trioxide aggregate, BiodentineTM and calcium hydroxide on viability, proliferation, migration and differentiation of stem cells from human exfoliated deciduous teeth

PubMed Central

Araújo, Leandro Borges; Cosme-Silva, Leopoldo; Fernandes, Ana Paula; de Oliveira, Thais Marchini; Cavalcanti, Bruno das Neves; Gomes, João Eduardo; Sakai, Vivien Thiemy

2018-01-01

Abstract Objective The aim of the study was to evaluate the effects of the capping materials mineral trioxide aggregate (MTA), calcium hydroxide (CH) and BiodentineTM (BD) on stem cells from human exfoliated deciduous teeth (SHED) in vitro. Material and Methods SHED were cultured for 1 – 7 days in medium conditioned by incubation with MTA, BD or CH (1 mg/mL), and tested for viability (MTT assay) and proliferation (SRB assay). Also, the migration of serum-starved SHED towards conditioned media was assayed in companion plates, with 8 μm-pore-sized membranes, for 24 h. Gene expression of dentin matrix protein-1 (DMP-1) was evaluated by reverse-transcription polymerase chain reaction. Regular culture medium with 10% FBS (without conditioning) and culture medium supplemented with 20% FBS were used as controls. Results MTA, CH and BD conditioned media maintained cell viability and allowed continuous SHED proliferation, with CH conditioned medium causing the highest positive effect on proliferation at the end of the treatment period (compared with BD and MTA) (p<0.05). In contrast, we observed increased SHED migration towards BD and MTA conditioned media (compared with CH) (p<0.05). A greater amount of DMP-1 gene was expressed in MTA group compared with the other groups from day 7 up to day 21. Conclusion Our results show that the three capping materials are biocompatible, maintain viability and stimulate proliferation, migration and differentiation in a key dental stem cell population. PMID:29412365

Effects of mineral trioxide aggregate, BiodentineTM and calcium hydroxide on viability, proliferation, migration and differentiation of stem cells from human exfoliated deciduous teeth.

PubMed

Araújo, Leandro Borges; Cosme-Silva, Leopoldo; Fernandes, Ana Paula; Oliveira, Thais Marchini de; Cavalcanti, Bruno das Neves; Gomes Filho, João Eduardo; Sakai, Vivien Thiemy

2018-02-01

The aim of the study was to evaluate the effects of the capping materials mineral trioxide aggregate (MTA), calcium hydroxide (CH) and BiodentineTM (BD) on stem cells from human exfoliated deciduous teeth (SHED) in vitro. SHED were cultured for 1 - 7 days in medium conditioned by incubation with MTA, BD or CH (1 mg/mL), and tested for viability (MTT assay) and proliferation (SRB assay). Also, the migration of serum-starved SHED towards conditioned media was assayed in companion plates, with 8 μm-pore-sized membranes, for 24 h. Gene expression of dentin matrix protein-1 (DMP-1) was evaluated by reverse-transcription polymerase chain reaction. Regular culture medium with 10% FBS (without conditioning) and culture medium supplemented with 20% FBS were used as controls. MTA, CH and BD conditioned media maintained cell viability and allowed continuous SHED proliferation, with CH conditioned medium causing the highest positive effect on proliferation at the end of the treatment period (compared with BD and MTA) (p<0.05). In contrast, we observed increased SHED migration towards BD and MTA conditioned media (compared with CH) (p<0.05). A greater amount of DMP-1 gene was expressed in MTA group compared with the other groups from day 7 up to day 21. Our results show that the three capping materials are biocompatible, maintain viability and stimulate proliferation, migration and differentiation in a key dental stem cell population.

Laboratory Synthesized Calcium Oxide and Calcium Hydroxide Grains: A Candidate to Explain the 6.8 Micron Band

NASA Technical Reports Server (NTRS)

Kimura, Yuki; Nuth, Joseph A., III

2005-01-01

We will demonstrate that CaO and Ca(OH)2 are excellent candidates to explain the 6.8 microns feature, which is one of the most obscure features in young stellar objects. We discuss the condensation of CaO grains and the potential formation of a Ca(OH)2 surface layer. The infrared spectra of these grains are compared with the spectra of fifteen young stellar objects. We note that CaO-rich grains are seen in all meteoritic CAIs (calcium-aluminum-rich inclusions) and the 6.8 micron feature has only been observed in young stellar objects. Therefore, we consider CaO grains to be a plausible candidate to explain the 6.8 microns feature and hypothesize that they are produced in the hot interiors of young stellar environments.

The alpha-form of the hydroxides of bivalent metals

NASA Technical Reports Server (NTRS)

Feitknecht, W.

1984-01-01

X-ray analyses were made of the hydroxides of the bivalent metals. The freshly pptd. hydroxide is usually in the alpha-form, which on standing is converted to another form or other forms. The alpha and c grating dimensions of the alpha-form and the C6-type of Co, Zn, C, Co-Zn and Ni-Zn hydroxides are tabulated. Ni hydroxide does not exhibit an alpha-form. The alpha-Co(OH)2, the blue form, is stabilized by sugar or by the higher alcohols: these compounds do not stabilize alpha-Zn(OH)2.

Self-Setting Calcium Orthophosphate Formulations

PubMed Central

Dorozhkin, Sergey V.

2013-01-01

In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are bioactive and biodegradable grafting bioceramics in the form of a powder and a liquid. After mixing, both phases form pastes, which set and harden forming either a non-stoichiometric calcium deficient hydroxyapatite or brushite. Since both of them are remarkably biocompartible, bioresorbable and osteoconductive, self-setting calcium orthophosphate formulations appear to be promising bioceramics for bone grafting. Furthermore, such formulations possess excellent molding capabilities, easy manipulation and nearly perfect adaptation to the complex shapes of bone defects, followed by gradual bioresorption and new bone formation. In addition, reinforced formulations have been introduced, which might be described as calcium orthophosphate concretes. The discovery of self-setting properties opened up a new era in the medical application of calcium orthophosphates and many commercial trademarks have been introduced as a result. Currently such formulations are widely used as synthetic bone grafts, with several advantages, such as pourability and injectability. Moreover, their low-temperature setting reactions and intrinsic porosity allow loading by drugs, biomolecules and even cells for tissue engineering purposes. In this review, an insight into the self-setting calcium orthophosphate formulations, as excellent bioceramics suitable for both dental and bone grafting applications, has been provided. PMID:24956191

Hydroxide-catalyzed bonding

NASA Technical Reports Server (NTRS)

Gwo, Dz-Hung (Inventor)

2003-01-01

A method of bonding substrates by hydroxide-catalyzed hydration/dehydration involves applying a bonding material to at least one surface to be bonded, and placing the at least one surface sufficiently close to another surface such that a bonding interface is formed between them. A bonding material of the invention comprises a source of hydroxide ions, and may optionally include a silicate component, a particulate filling material, and a property-modifying component. Bonding methods of the invention reliably and reproducibly provide bonds which are strong and precise, and which may be tailored according to a wide range of possible applications. Possible applications for bonding materials of the invention include: forming composite materials, coating substrates, forming laminate structures, assembly of precision optical components, and preparing objects of defined geometry and composition. Bonding materials and methods of preparing the same are also disclosed.

Residual antibiofilm effects of various concentrations of double antibiotic paste used during regenerative endodontics after different application times.

PubMed

Jenks, Daniel B; Ehrlich, Ygal; Spolnik, Kenneth; Gregory, Richard L; Yassen, Ghaeth H

2016-10-01

We investigated the residual antibiofilm effects of different concentrations of double antibiotic paste (DAP) applied on radicular dentin for 1 or 4 weeks. Dentin samples were prepared (n=120), sterilized and pretreated for 1 or 4 weeks with the clinically used concentration of DAP (500mg/mL), low concentrations of DAP (1, 5 or 50mg/mL) loaded into a methylcellulose system, calcium hydroxide (Ca(OH) 2 ), or placebo paste. After the assigned treatment time, treatment pastes were rinsed off and the samples were kept independently in phosphate buffered saline for 3 weeks. Pretreated dentin samples were then inoculated with Enterococcus faecalis and bacterial biofilms were allowed to grow for an additional 3 weeks. Biofilms were then retrieved from dentin using biofilm disruption assays, diluted, spiral plated, and quantified. Fisher's Exact and Wilcoxon rank sum tests were used for statistical comparisons (α=0.05). Dentin pretreatment for 4 weeks with 5, 50 or 500mg/mL of DAP demonstrated significantly higher residual antibiofilm effects and complete eradication of E. faecalis biofilms in comparison to a 1 week pretreatment with similar concentrations. However, dentin pretreated with 1mg/mL of DAP or Ca(OH) 2 did not provide a substantial residual antibiofilm effect regardless of the application time. Dentin pretreatment with 5mg/mL of DAP or higher for 4 weeks induced significantly higher residual antibiofilm effects in comparison to a 1 week pretreatment with the same concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Leaching Behavior of Calcium Ions on Compression and Durability of Cement-Based Materials with Mineral Admixtures

PubMed Central

Cheng, An; Chao, Sao-Jeng; Lin, Wei-Ting

2013-01-01

Leaching of calcium ions increases the porosity of cement-based materials, consequently resulting in a negative effect on durability since it provides an entry for aggressive harmful ions, causing reinforcing steel corrosion. This study investigates the effects of leaching behavior of calcium ions on the compression and durability of cement-based materials. Since the parameters influencing the leaching behavior of cement-based materials are unclear and diverse, this paper focuses on the influence of added mineral admixtures (fly ash, slag and silica fume) on the leaching behavior of calcium ions regarding compression and durability of cemented-based materials. Ammonium nitrate solution was used to accelerate the leaching process in this study. Scanning electron microscopy, X-ray diffraction analysis, and thermogravimetric analysis were employed to analyze and compare the cement-based material compositions prior to and after calcium ion leaching. The experimental results show that the mineral admixtures reduce calcium hydroxide quantity and refine pore structure through pozzolanic reaction, thus enhancing the compressive strength and durability of cement-based materials. PMID:28809247

Effects of casein phosphopeptide amorphous calcium fluoride phosphate paste on white spot lesions and dental plaque after orthodontic treatment: a 3-month follow-up.

PubMed

Beerens, M W; van der Veen, M H; van Beek, H; ten Cate, J M

2010-12-01

The effects of casein phosphopeptide amorphous calcium fluoride phosphate (CPP-ACFP) paste vs. control paste on the remineralization of white spot caries lesions and on plaque composition were tested in a double-blind prospective randomized clinical trial. Fifty-four orthodontic patients, with multiple white spot lesions observed upon the removal of fixed appliances, were followed up for 3 months. Subjects were included and randomly assigned to either CPP-ACFP paste or control paste, for use supplementary to their normal oral hygiene. Caries regression was assessed on quantitative light-induced fluorescence (QLF) images captured directly after debonding and 6 and 12 wk thereafter. The total counts and proportions of aciduric bacteria, Streptococcus mutans, and Lactobacillus spp. were measured in plaque samples obtained just before debonding, and 6 and 12 wk afterwards. A significant decrease in fluorescence loss was found with respect to baseline for both groups and no difference was found between groups. The size of the lesion area did not change significantly over time or between the groups. The percentages of aciduric bacteria and of S. mutans decreased from 47.4 to 38.1% and from 9.6 to 6.6%, respectively. No differences were found between groups. We observed no clinical advantage for use of the CPP-ACFP paste supplementary to normal oral hygiene over the time span of 12 wk. © 2010 Eur J Oral Sci.

Inhibitory effect of betel quid on the volatility of methyl mercaptan.

PubMed

Wang, C K; Chen, S L; Wu, M G

2001-04-01

Betel quid, a popular natural masticatory in Taiwan, is mainly composed of fresh areca fruit, Piper betle (leaf or inflorescence), and slaked lime paste. People say that halitosis disappears during betel quid chewing. In this study, the removal of mouth odor during betel quid chewing was discussed by using a model system which measured its inhibition on the volatility of methyl mercaptan. Results showed that crude extracts of betel quid (the mixture of areca fruit, Piper betle, and slaked lime paste) and extracts of the mixture of areca fruit and slaked lime paste exhibited marked effects on the volatility of methyl mercaptan, and the inhibition function increased when increasing amounts of slaked lime paste were added. The same condition (increased inhibition) was also found by replacing the slaked lime paste with alkaline salts (calcium hydroxide, potassium hydroxide, or sodium hydroxide). Areca fruit, the major ingredient of betel quid, contained abundant phenolics. However, the crude phenolic extract of areca fruit did not show any inhibitory activity on the volatility of methyl mercaptan. Great inhibitory activity occurred only when the crude phenolic extract of areca fruit was treated with alkali. Further studies by using gel filtration determined that the effect probably came from the oxidative polymerization of phenolics of areca fruit after alkaline treatment.

Inclusion of calcium hydroxide-treated corn stover as a partial forage replacement in diets for lactating dairy cows.

PubMed

Casperson, Brittany A; Wertz-Lutz, Aimee E; Dunn, Jim L; Donkin, Shawn S

2018-03-01

Chemical treatment may improve the nutritional value of corn crop residues, commonly referred to as corn stover, and the potential use of this feed resource for ruminants, including lactating dairy cows. The objective of this study was to determine the effect of prestorage chopping, hydration, and treatment of corn stover with Ca(OH) 2 on the feeding value for milk production, milk composition, and dry matter intake (DMI). Multiparous mid-lactation Holstein cows (n = 30) were stratified by parity and milk production and randomly assigned to 1 of 3 diets. Corn stover was chopped, hydrated, and treated with 6% Ca(OH) 2 (as-fed basis) and stored in horizontal silo bags. Cows received a control (CON) total mixed ration (TMR) or a TMR in which a mixture of treated corn stover and distillers grains replaced either alfalfa haylage (AHsub) or alfalfa haylage and an additional portion of corn silage (AH+CSsub). Treated corn stover was fed in a TMR at 0, 15, and 30% of the diet DM for the CON, AHsub, and AH+CSsub diets, respectively. Cows were individually fed in tiestalls for 10 wk. Milk production was not altered by treatment. Compared with the CON diet, DMI was reduced when the AHsub diet was fed and tended to be reduced when cows were fed the AH+CSsub diet (25.9, 22.7, and 23.1 ± 0.88 kg/d for CON, AHsub, and AH+CSsub diets, respectively). Energy-corrected milk production per unit of DMI (kg/kg) tended to increase with treated corn stover feeding. Milk composition, energy-corrected milk production, and energy-corrected milk per unit of DMI (kg/kg) were not different among treatments for the 10-wk feeding period. Cows fed the AHsub and AH+CSsub diets had consistent DMI over the 10-wk treatment period, whereas DMI for cows fed the CON diet increased slightly over time. Milk production was not affected by the duration of feeding. These data indicate that corn stover processing, prestorage hydration, and treatment with calcium hydroxide can serve as an alternative to

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

21 CFR 73.1326 - Chromium hydroxide green.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Chromium hydroxide green. 73.1326 Section 73.1326 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1326 Chromium hydroxide green. (a) Identity. (1...

Clinical evaluation of the efficacy of an in-office desensitizing paste containing 8% arginine and calcium carbonate in providing instant and lasting relief of dentin hypersensitivity.

PubMed

Schiff, Thomas; Delgado, Evaristo; Zhang, Yun Po; Cummins, Diane; DeVizio, William; Mateo, Luis R

2009-03-01

To determine the efficacy of an in-office desensitizing paste containing 8% arginine and calcium carbonate relative to that of a commercially-available pumice prophylaxis paste in reducing dentin hypersensitivity instantly after a single application following a dental scaling procedure and to establish the duration of sensitivity relief over a period of 4 weeks and 12 weeks. This was a single-center, parallel group, double-blind, stratified clinical study conducted in San Francisco, California, USA. Qualifying adult male and female subjects who presented two hypersensitive teeth with a tactile hypersensitivity score (Yeaple Probe) between 10-50 grams of force and an air blast hypersensitivity score of 2 or 3 (Schiff Cold Air Sensitivity Scale) were stratified according to their baseline hypersensitivity scores and randomly assigned within strata to one of two treatment groups: (1) A Test Paste, a desensitizing paste containing 8% arginine and calcium carbonate (Colgate-Palmolive Co); and (2) A Control Paste, Nupro pumice prophylaxis paste (Dentsply Professional). Subjects received a professionally-administered scaling procedure, after which they were re-examined for tactile and air blast dentin hypersensitivity (Post-Scaling Examinations). The assigned pastes were then applied as the final step to the professional dental cleaning procedure. Tactile and air blast dentin hypersensitivity examinations were again performed immediately after paste application. Subjects were provided with a commercially-available non-desensitizing dentifrice containing 0.243% sodium fluoride (Crest Cavity Protection, Procter & Gamble Co.) and an adult soft-bristled toothbrush and were instructed to brush their teeth for 1 minute, twice daily at home using only the toothbrush and dentifrice provided, for the next 12 weeks. Subjects returned to the testing facility 4 and 12 weeks after the single application of Test or Control paste, having refrained from all oral hygiene procedures and

Effect of addition of lycopene to calcium hydroxide and chlorhexidine as intracanal medicament on fracture resistance of radicular dentin at two different time intervals: An in vitro study.

PubMed

Madhusudhana, Koppolu; Archanagupta, Kasamsetty; Suneelkumar, Chinni; Lavanya, Anumula; Deepthi, Mandava

2015-01-01

Long-term use of intracanal medicaments such as calcium hydroxide (CH) reduces the fracture resistance of dentin. The present study was undertaken to evaluate the fracture resistance of radicular dentin on long-term use of CH, chlorhexidine (CHX) with lycopene (LP). To compare the fracture resistance of radicular dentin when intracanal medicaments such as CH, CHX with LP were used for 1-week and 1-month time interval. Sixty single-rooted extracted human permanent premolars were collected, and complete instrumentation was done. Samples were divided into three groups based on intracanal medicament used. Group 1 - no medicament was placed (CON), group 2 - mixture of 1.5 g of CH and 1 ml of 2% CHX (CHCHX), group 3 - mixture of 1.5 g of CH, 1 ml of CHX and 1 ml of 5% LP solution (CHCHXLP). After storage period of each group for 1-week and 1-month, middle 8 mm root cylinder was sectioned and tested for fracture resistance. Results were analyzed using paired t-test. At 1-month time interval, there was a statistically significant difference in fracture resistance between CHCHX and CHCHXLP groups. Addition of LP has not decreased the fracture resistance of radicular dentin after 1-month.

Calcium supplementation and cardiovascular risk: A rising concern.

PubMed

Tankeu, Aurel T; Ndip Agbor, Valirie; Noubiap, Jean Jacques

2017-06-01

Over the past decade, the number of individuals taking calcium supplementation worldwide has been on the rise, especially with the emergence of new pharmaceutical companies specialized in the marketing of dietary supplements; with calcium supplementation being their main business axis. This is mostly because of the established role of calcium in the prevention and treatment of osteoporosis and, to a lesser extent, its role in the prevention of fractures. Recently, a rising body of evidence on the adverse effect of calcium supplementation on nonskeletal, especially cardiovascular, health has been a cause for concern. In fact, a significant number of studies have reported an association between calcium supplementation and adverse cardiovascular events, even though high dietary calcium intake was shown to have a protective effect. The mechanism by which calcium supplementation could cause a cardiovascular event was still unclear until a recent study published in the Journal of the American Heart Association. Combining this recent finding with available data associating calcium supplementation with cardiovascular mortality and all-cause mortality, we call on the need for an evidence-based approach to calcium supplementation, while stressing on the safety of dietary calcium intake over the former on cardiovascular health. ©2017 Wiley Periodicals, Inc.

Calcium Orthophosphate Cements and Concretes

PubMed Central

Dorozhkin, Sergey V.

2009-01-01

In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA) or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone), calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

Study of nickel hydroxide electrodes. 2: Oxidation products of nickel (2) hydroxides

NASA Technical Reports Server (NTRS)

Bode, H.; Demelt, K.; White, J.

1986-01-01

Pure phases of some oxidized Ni oxides were prepared galvanimetrically with the Ni(2) hydroxide electrode of an alkaline battery. The crystallographic data of these phases, their chemical behavior, and conditions of transition were studied.

Evaluation of layered zinc hydroxide nitrate and zinc/nickel double hydroxide salts in the removal of chromate ions from solutions

NASA Astrophysics Data System (ADS)

de Oliveira, Henrique Bortolaz; Wypych, Fernando

2016-11-01

Layered zinc hydroxide nitrate (ZnHN) and Zn/Ni layered double hydroxide salts were synthesized and used to remove chromate ions from solutions at pH 8.0. The materials were characterized by many instrumental techniques before and after chromate ion removal. ZnHN decomposed after contact with the chromate solution, whereas the layered structure of Zn/Ni hydroxide nitrate (Zn/NiHN) and Zn/Ni hydroxide acetate (Zn/NiHA) remained their layers intact after the topotactic anionic exchange reaction, only changing the basal distances. ZnHN, Zn/NiHN, and Zn/NiHA removed 210.1, 144.8, and 170.1 mg of CrO42-/g of material, respectively. Although the removal values obtained for Zn/NiHN and Zn/NiHA were smaller than the values predicted for the ideal formulas of the solids (194.3 and 192.4 mg of CrO42-/g of material, respectively), the measured capacities were higher than the values achieved with many materials reported in the literature. Kinetic experiments showed the removal reaction was fast. To facilitate the solid/liquid separation process after chromium removal, Zn/Ni layered double hydroxide salts with magnetic supports were also synthesized, and their ability to remove chromate was evaluated.

Cu2+ ions as a paramagnetic probe to study the surface chemical modification process of layered double hydroxides and hydroxide salts with nitrate and carboxylate anions.

PubMed

Arizaga, Gregorio Guadalupe Carbajal; Mangrich, Antonio Salvio; Wypych, Fernando

2008-04-01

A layered zinc hydroxide nitrate (Zn5(OH)8(NO3)2.2H2O) and a layered double hydroxide (Zn/Al-NO3) were synthesized by coprecipitation and doped with different amounts of Cu2+ (0.2, 1, and 10 mol%), as paramagnetic probe. Although the literature reports that the nitrate ion is free (with D3h symmetry) between the layers of these two structures, the FTIR spectra of two zinc hydroxide nitrate samples show the C2v symmetry for the nitrate ion, whereas the g ||/A || value in the EPR spectra of Cu2+ is high. This fact suggests bonding of some nitrate ions to the layers of the zinc hydroxide nitrate. The zinc hydroxide nitrate was used as matrix in the intercalation reaction with benzoate, o-chlorobenzoate, and o-iodobenzoate ions. FTIR spectra confirm the ionic exchange reaction and the EPR spectroscopy reveals bonding of the organic ions to the inorganic layers of the zinc hydroxide nitrate, while the layered double hydroxides show only exchange reactions.

Enhancing the antibacterial activity of the gold standard intracanal medicament with incorporation of silver zeolite: An in vitro study.

PubMed

Ghatole, Kiran; Gowdra, Ramesh Halebathi Giriyappa; Azher, Samer; Sabharwal, Sumit; Singh, Veerandar T; Sundararajan, Bharath Vardhana

2016-01-01

Enterococcus faecalis is a persistent organism that plays a major role in the etiology of persistent periradicular lesions after root canal treatment has been associated with different forms of periradicular disease including primary endodontic infections and persistent infections. The present study compares the antibacterial activities of calcium hydroxide, calcium hydroxide mixed with silver zeolite, and calcium hydroxide mixed with 2% chlorhexidine against E. faecalis using direct contact test. The test materials of the in vitro experimental study were grouped as group 1-calcium hydroxide mixed with sterile water, group 2-2% silver zeolite added in calcium hydroxide mixed with sterile water, and group 3-calcium hydroxide mixed with 2% chlorhexidine. The bottom of microtiter plate were coated with freshly mixed tested material and a 10 μL of bacterial suspension was placed. After 1 h of incubation at 37°C, brain-heart infusion (BHI) broth (245 μL) was added and mixed for 2 min. These were designated as "subgroup 1" wells. A volume of 15 μL of broth then transferred from subgroup 1 wells to an adjacent set of four wells containing fresh BHI medium (215 μL); these wells were designated as "subgroup 2"' wells. The optical density was measured by a spectrophotometer after the first day, third day, and seventh day. One-way analysis of variance (ANOVA) and Tukey tests were performed for the analysis. Calcium hydroxide mixed with silver zeolite showed maximum antibacterial activity. Silver zeolite can be added in calcium hydroxide to enhance the latter's antibacterial activity against E. faecalis.

Extraction of starch from hulled and hull-less barley with papain and aqueous sodium hydroxide.

PubMed

Sharma, Priyanka; Tejinder, S

2014-12-01

Starch was isolated from hulled (VJM 201) and hull-less (BL 134) barley with papain and aqueous sodium hydroxide treatments. For enzyme-assisted extraction, barley was steeped in water containing 0.2 % SO2 + 0.55 % lactic acid at 50° ± 2 °C for 4-5 h. The slurry was mixed with 0.4-2.0 g papain/kg barley and incubated at 50° ± 2 °C for 1-5 h. Aqueous sodium hydroxide (0.01-0.05 M) was added to the finely ground barley meal. The alkaline slurry was incubated at ambient temperature (25° ± 2 °C) for 15-60 min. The starch and grain fractions were isolated by screening and centrifugation. Increases in the time of treatment significantly affected the fiber, centrifugation and non-starch residue losses. Concentration of papain and sodium hydroxide had negligible effect on extraction losses. The enzyme-assisted extraction efficiency of starch was higher (80.7-84.6 %) than the alkaline method (70.9-83.7 %). The hulled barley showed higher extraction efficiency than the hull-less barley. The slurry treated with 0.4 g papain/kg barley for 5 h and 0.03 M sodium hydroxide for 60 min produced maximal yield of starch. Barley starch showed desirably high pasting temperature, water binding capacity and hold viscosity; and low final and setback viscosity compared with the commercial corn starch. The alkaline extracted hull-less barley starch showed exceptionally high peak and hold viscosities.

Interaction between calcium and phosphate adsorption on goethite.

PubMed

Rietra, R P; Hiemstra, T; van Riemsdijk, W H

2001-08-15

Quantitatively, little is known about the ion interaction processes that are responsible for the binding of phosphate in soil, water, and sediment, which determine the bioavailability and mobility of phosphate. Studies have shown that metal hydroxides are often responsible for the binding of PO4 in soils and sediments, but the binding behavior of PO4 in these systems often differs significantly from adsorption studies on metal hydroxides in laboratory. The interaction between PO4 and Ca adsorption was studied on goethite because Ca can influence the PO4 adsorption equilibria. Since adsorption interactions are very difficult to discriminate from precipitation reactions, conditions were chosen to prevent precipitation of Ca-PO4 solids. Adsorption experiments of PO4 and Ca, individually and in combination, show a strong interaction between adsorbed Ca and PO4 on goethite for conditions below the saturation index of apatite. It is shown that it is possible to predict the adsorption and interaction of PO4 and Ca on electrostatic arguments using the model parameter values derived from the single-ion systems and without invoking ternary complex formation or precipitation. The model enables the prediction of the Ca-PO4 interaction for environmentally relevant calcium and phosphate concentrations.

High-temperature characteristics of advanced Ni-MH batteries using nickel electrodes containing CaF 2

NASA Astrophysics Data System (ADS)

Zhang, Xuezeng; Gong, Zhixin; Zhao, Shumei; Geng, Mingming; Wang, Yan; Northwood, Derek O.

The high-temperature charge acceptance of Ni-MH batteries has been improved through the addition of calcium fluoride to the pasted nickel hydroxide electrode made using spherical Co(OH) 2-coated nickel hydroxide powder. The charge acceptance of the Ni-MH battery at 60 °C is over 95% at 1 C charge/discharge rates. The charge acceptance at 60 °C remains at over 90% through 10 cycles. The use of Co(OH) 2-coated Ni(OH) 2 plus a CaF 2 addition to the positive electrode also significantly improved the high-temperature stability in terms of reduced gas evolution.

Calcium-enriched mixture cement as artificial apical barrier: A case series

PubMed Central

Nosrat, Ali; Asgary, Saeed; Eghbal, Mohammad Jafar; Ghoddusi, Jamileh; Bayat-Movahed, Saeed

2011-01-01

In comparison to the conventional apexification using calcium hydroxide, artificial apical barrier technique is more valuable and less time consuming. This article describes successful use of calcium-enriched mixture (CEM) cement as an artificial apical barrier in open apices. In this study, 13 single-rooted teeth with necrotic pulps and open apices were treated non-surgically. After copious irrigation of the root canals with NaOCl 5.25% and gentle filing, based on need for interappointment dressing, treatments were followed by CEM cement (BioniqueDent, Tehran, Iran) apical plug insertion in the first or second appointment. All cases were then permanently restored. All subjects were followed until radiographic evidence of periradicular healing was seen (mean 14.5 months). Clinically, all cases were functional and asymptomatic and complete osseous healing was observed in all the teeth. Considering the biological properties of CEM cement, this new endodontic biomaterial might be appropriate to be used as artificial apical barrier in the open apex teeth. PMID:22144818

Review of calcium methodologies.

PubMed

Zak, B; Epstein, E; Baginski, E S

1975-01-01

A review of calcium methodologies for serum has been described. The analytical systems developed over the past century have been classified as to type beginning with gravimetry and extending to isotope dilution-mass spectrometry by covering all of the commonly used technics which have evolved during that period. Screening and referee procedures are discussed along with comparative sensitivities encountered between atomic absorption spectrophotometry and molecular absorption spectrophotometry. A procedure involving a simple direct reaction for serum calcium using cresolphthalein complexone is recommended in which high blanks are minimized by repressing the ionization of the color reagent on lowering the dielectric constant characteristics of the mixture with dimethylsulfoxide. Reaction characteristics, errors which can be encountered, normal ranges and an interpretative resume are included in its discussion.

[Comparative study of the antimicrobial effect of various cavity liners used in conservative dentistry].

PubMed

Pumarola Suñé, J; Espias Gómez, A; Canalda Sahli, C

1989-01-01

We have compared the microbiological activity of the following cavity liners: Life, Dycal II, Calcipulpe, Pure calcium hydroxide and Cavitec; against five different bacterial strains: Veillonella parvula, Bacteroides fragilis, Peptococcus s.p., Staphylococcus aureus, and Streptococcus beta hemolytic: The results demonstrate the higher antimicrobial activity of the manufactured cavity liners with calcium hydroxide base in comparison with the pure calcium hydroxide.

Pore Structure Characterization of Sodium Hydroxide Activated Slag Using Mercury Intrusion Porosimetry, Nitrogen Adsorption, and Image Analysis.

PubMed

Zuo, Yibing; Ye, Guang

2018-06-19

The pore structure of alkali-activated slag has a significant influence on its performance. However, the literature shows insufficient studies regarding the suitability of different techniques for characterizing the pore structure and the influences of Na₂O and curing age on pore structure development. In pursuit of a better understanding, the pore structure of sodium hydroxide activated slag paste was characterized by multiple techniques, e.g., mercury intrusion porosimetry (MIP), nitrogen (N₂) adsorption, and scanning electron microscopy (SEM) image analysis. The sodium hydroxide activated slag pastes were prepared with three different contents of Na₂O (Na₂O/slag = 4, 6, and 8%) and cured for different times up to 360 days. The microstructure observation reveals that outer C⁻(N⁻)A⁻S⁻H and inner C⁻(N⁻)A⁻S⁻H grow successively around the reacting slag grains, along with crystalline reaction products which are formed in the empty coarse pore space. The increase of Na₂O content and curing age lead to a finer pore structure. The MIP measurements show that the total porosity drops about 70% within the first day, and that one peak at most, corresponding to gel pores, was identified in the differential curves of all the investigated samples from 1 to 360 days. On the contrary, only one peak, corresponding to capillary pores, was identified by SEM-image analysis. The differential curves derived from N₂ adsorption generally reveal two peaks, and the trend that the pore diameters of those two peaks vary with curing age depends on the content of Na₂O. Compared to Portland cement, sodium hydroxide activated slag has a higher pore space filling capacity ( χ , V products / V slag-reacted ), while the capacity decreases with increasing Na₂O content and curing age.

Intercalation studies of zinc hydroxide chloride: Ammonia and amino acids

NASA Astrophysics Data System (ADS)

Arízaga, Gregorio Guadalupe Carbajal

2012-01-01

Zinc hydroxide chloride (ZHC) is a layered hydroxide salt with formula Zn5(OH)8Cl2·2H2O. It was tested as intercalation matrix for the first time and results were compared with intercalation products of the well-known zinc hydroxide nitrate and a Zn/Al layered double hydroxide. Ammonia was intercalated into ZHC, while no significant intercalation occurred in ZHN. Aspartic acid intercalation was only achieved by co-precipitation at pH=10 with ZHC and pH=8 with zinc hydroxide nitrate. Higher pH resistance in ZHC favored total deprotonation of both carboxylic groups of the Asp molecule. ZHC conferred more thermal protection against Asp combustion presenting exothermic peaks even at 452 °C while the exothermic event in ZHN was 366 °C and in the LDH at 276 °C.

21 CFR 73.1010 - Alumina (dried aluminum hydroxide).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Alumina (dried aluminum hydroxide). 73.1010 Section 73.1010 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES...) Specifications. Alumina (dried aluminum hydroxide) shall conform to the following specifications: Acidity or...

Spectroscopic investigation of Ni speciation in hardened cement paste.

PubMed

Vespa, M; Dähn, R; Grolimund, D; Wieland, E; Scheidegger, A M

2006-04-01

Cement-based materials play an important role in multi-barrier concepts developed worldwide for the safe disposal of hazardous and radioactive wastes. Cement is used to condition and stabilize the waste materials and to construct the engineered barrier systems (container, backfill, and liner materials) of repositories for radioactive waste. In this study, Ni uptake by hardened cement paste has been investigated with the aim of improving our understanding of the immobilization process of heavy metals in cement on the molecular level. X-ray absorption spectroscopy (XAS) coupled with diffuse reflectance spectroscopy (DRS) techniques were used to determine the local environment of Ni in cement systems. The Ni-doped samples were prepared at two different water/cement ratios (0.4, 1.3) and different hydration times (1 hour to 1 year) using a sulfate-resisting Portland cement. The metal loadings and the metal salts added to the system were varied (50 up to 5000 mg/kg; NO3(-), SO4(2-), Cl-). The XAS study showed that for all investigated systems Ni(ll) is predominantly immobilized in a layered double hydroxide (LDH) phase, which was corroborated by DRS measurements. Only a minor extent of Ni(ll) precipitates as Ni-hydroxides (alpha-Ni(OH)2 and beta-Ni(OH)2). This finding suggests that Ni-Al LDH, rather than Ni-hydroxides, is the solubility-limiting phase in the Ni-doped cement system.

Chemical matricectomy with sodium hydroxide: long-term follow-up results.

PubMed

Bostanci, Seher; Kocyigit, Pelin; Parlak, Nehir; Gungor, Hilayda Karakok

2014-11-01

Chemical matricectomy with sodium hydroxide is a method being used successfully in the treatment of ingrown toenail. In this study, it was aimed to evaluate long-term recurrence rates after chemical matricectomy using sodium hydroxide application of different durations. Two hundred two patients with ingrown nail edges were treated with either 1-minute (Group 1) or 2-minute (Group 2) applications of sodium hydroxide matricectomy. All patients were followed for at least 2 years. Chemical matricectomy with sodium hydroxide was applied to a total of 585 nail edges of 202 cases. The overall recurrence rates in Group 1 and Group 2 were 6.4% and 7.1%, respectively, during the average 7.5-year follow-up period. No statistically significant differences were detected in terms of recurrence between the 2 groups (p = .73). Chemical matricectomy with sodium hydroxide is an easy method in the treatment of ingrown nails, with low morbidity and high success rates. There was no difference between 1-minute and 2-minute applications in terms of recurrence during the long-term follow-up. Chemical matricectomy with 1-minute application of sodium hydroxide showed high success in terms of long-term follow-up results.

Lifetime of Sodium Beta-Alumina Membranes in Molten Sodium Hydroxide

DTIC Science & Technology

2008-07-01

ABSTRACT Summary: Sodium metal can be made by electrolysis of molten sodium hydroxide in sodium beta-alumina membrane electrolysis cells... electrolysis of molten sodium hydroxide in sodium ”-alumina membrane electrolysis cells. However, there are some uncertainties about the lifetime of the...the properties of the membrane degrade upon long term contact with molten sodium hydroxide. Electrolysis cells were designed, but it proved

Nickel hydroxide/cobalt-ferrite magnetic nanocatalyst for alcohol oxidation.

PubMed

Bhat, Pooja B; Inam, Fawad; Bhat, Badekai Ramachandra

2014-08-11

A magnetically separable, active nickel hydroxide (Brønsted base) coated nanocobalt ferrite catalyst has been developed for oxidation of alcohols. High surface area was achieved by tuning the particle size with surfactant. The surface area of 120.94 m2 g(-1) has been achieved for the coated nanocobalt ferrite. Improved catalytic activity and selectivity were obtained by synergistic effect of transition metal hydroxide (basic hydroxide) on nanocobalt ferrite. The nanocatalyst oxidizes primary and secondary alcohols efficiently (87%) to corresponding carbonyls in good yields.

Antimicrobial activity of short- and medium-term applications of polyhexamethylene biguanide, chlorhexidine digluconate and calcium hydroxide in infected immature bovine teeth in vitro.

PubMed

Zaugg, Lucia K; Zitzmann, Nicola U; Hauser-Gerspach, Irmgard; Waltimo, Tuomas; Weiger, Roland; Krastl, Gabriel

2014-08-01

To compare the antimicrobial activity of polyhexamethylene biguanide (Prontosan wound gel, Pr) and chlorhexidine digluconate (CHX) after short- and medium-term application with the disinfection ability of calcium hydroxide (Ca) in a model using immature bovine teeth. Sixty immature bovine roots were infected with Enterococcus faecalis and randomly assigned to six groups (n = 10). Disinfectants were applied into the root canal for 10 min (CHX-10 min and Pr-10 min) or 7 days (CHX-7d, Pr-7d and Ca-7d(g) ). In the negative control group (Co-n), no disinfectant was used. Dentine samples were collected, and the total count of bacteria and colony-forming units were determined. The log10 -transformed Colony-forming units (CFU) data were analysed using a Kruskal-Wallis test with post hoc Wilcoxon multiple-comparison tests. The application of disinfectants led to a significant reduction in CFUs in all groups compared with group Co-n. When compared to Ca-7d(g) , CHX-7d (P = 0.290), CHX-10 min (P = 0.963) and Pr-7d (P = 0.095) revealed no significant differences. Pr-10 min had a significantly higher CFU value than Ca-7d(g) (P = 0.0004), CHX-10 min (P = 0.0009) and Pr-7d (P = 0.0006). Within the limitations of this study, sufficient antimicrobial effect may be reached by a short-term application of CHX. For the application of 1% Prontosan wound gel, a medium-term use (7 day) is required, while short-term use (10 min) is less effective. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

PubMed Central

Agrawal, Nikita; Shashikiran, N. D.; Singla, Shilpy; Ravi, K. S.; Kulkarni, Vinaya Kumar

2014-01-01

Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks. PMID:24808700

Neutralization of Hydroxide Ion in Melt-Grown NaCl Crystals

NASA Technical Reports Server (NTRS)

Otterson, Dumas A.

1961-01-01

Many recent studies of solid-state phenomena, particularly in the area of crystal imperfections, have involved the use of melt-grown NaCl single crystals. Quite often trace impurities in these materials have had a prominent effect on these phenomena. Trace amounts of hydroxide ion have been found in melt-grown NaCl crystals. This paper describes a nondestructive method of neutralizing the hydroxide ion in such crystals. Crystals of similar hydroxide content are maintained at an elevated temperature below the melting point of NaCl in a flowing atmosphere containing. dry hydrogen chloride. Heat treatment is continued until an analysis of the test specimens shows no excess hydroxide ion. A colorimetric method previously described4 is used for this analysis.

Isotopic evidence for variations in the marine calcium cycle over the Cenozoic.

PubMed

De La Rocha, C L; DePaolo, D J

2000-08-18

Significant variations in the isotopic composition of marine calcium have occurred over the last 80 million years. These variations reflect deviations in the balance between inputs of calcium to the ocean from weathering and outputs due to carbonate sedimentation, processes that are important in controlling the concentration of carbon dioxide in the atmosphere and, hence, global climate. The calcium isotopic ratio of paleo-seawater is an indicator of past changes in atmospheric carbon dioxide when coupled with determinations of paleo-pH.

40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

40 CFR 721.10573 - Magnesium hydroxide surface treated with substituted alkoxysilanes (generic).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Magnesium hydroxide surface treated... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10573 Magnesium hydroxide surface... to reporting. (1) The chemical substance identified generically as magnesium hydroxide surface...

DOUBLE SHELL TANK (DST) HYDROXIDE DEPLETION MODEL FOR CARBON DIOXIDE ABSORPTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

OGDEN DM; KIRCH NW

2007-10-31

This document generates a supernatant hydroxide ion depletion model based on mechanistic principles. The carbon dioxide absorption mechanistic model is developed in this report. The report also benchmarks the model against historical tank supernatant hydroxide data and vapor space carbon dioxide data. A comparison of the newly generated mechanistic model with previously applied empirical hydroxide depletion equations is also performed.

Arsenic removal from water

DOEpatents

Moore, Robert C [Edgewood, NM; Anderson, D Richard [Albuquerque, NM

2007-07-24

Methods for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical methods for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A method for continuous removal of arsenic from water is provided. Also provided is a method for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

System for removal of arsenic from water

DOEpatents

Moore, Robert C.; Anderson, D. Richard

2004-11-23

Systems for removing arsenic from water by addition of inexpensive and commonly available magnesium oxide, magnesium hydroxide, calcium oxide, or calcium hydroxide to the water. The hydroxide has a strong chemical affinity for arsenic and rapidly adsorbs arsenic, even in the presence of carbonate in the water. Simple and commercially available mechanical systems for removal of magnesium hydroxide particles with adsorbed arsenic from drinking water can be used, including filtration, dissolved air flotation, vortex separation, or centrifugal separation. A system for continuous removal of arsenic from water is provided. Also provided is a system for concentrating arsenic in a water sample to facilitate quantification of arsenic, by means of magnesium or calcium hydroxide adsorption.

Method of purifying isosaccharinate

DOEpatents

Rai, Dhanpat; Moore, Robert C.; Tucker, Mark D.

2010-09-07

A method of purifying isosaccharinate by mixing sodium carbonate, potassium carbonate, sodium hydroxide or potassium hydroxide with calcium isosaccharinate, removing the precipitated calcium carbonate and adjusting the pH to between approximately 4.5 to 5.0 thereby removing excess carbonate and hydroxide to provide an acidic solution containing isosaccharinate.

Effect of ammonium hydroxide on ultrastructure and tenderness of buffalo meat.

PubMed

Naveena, B M; Kiran, M; Reddy, K Sudhakar; Ramakrishna, C; Vaithiyanathan, S; Devatkal, Suresh K

2011-08-01

This study was conducted with an objective to improve the tenderness of tough buffalo meat using ammonium hydroxide. Buffalo meat chunks from Biceps femoris muscle were marinated with distilled water (control), 0.1%, 0.5% and 1.0% solution of ammonium hydroxide for 48 h at 4±1 °C and subjected to various physico-chemical analysis and ultrastructural studies. Ammonium hydroxide increased (P<0.05) the pH, water holding capacity (WHC), collagen solubility, total and salt soluble protein extractability and cooking yield. Reduction (P<0.05) in Warner-Bratzler shear force values were observed in all ammonium hydroxide treated samples compared to non-treated control. Electrophoretic pattern of muscle proteins exhibited reduction in the intensity and number of certain protein bands for 0.1% and 0.5% ammonium hydroxide treated samples compared to control. Scanning and transmission electron microscopy also revealed breakdown of endothelium layers surrounding muscle fibers and weakening of Z-discs respectively, in treated samples compared to controls. These results suggest that ammonium hydroxide might be used to tenderize tough buffalo meat. Copyright © 2011 Elsevier Ltd. All rights reserved.

Arsenic removal from contaminated brackish sea water by sorption onto Al hydroxides and Fe phases mobilized by land-use.

PubMed

Yu, Changxun; Peltola, Pasi; Nystrand, Miriam I; Virtasalo, Joonas J; Österholm, Peter; Ojala, Antti E K; Hogmalm, Johan K; Åström, Mats E

2016-01-15

This study examines the spatial and temporal distribution patterns of arsenic (As) in solid and aqueous materials along the mixing zone of an estuary, located in the south-eastern part of the Bothnian Bay and fed by a creek running through an acid sulfate (AS) soil landscape. The concentrations of As in solution form (<1 kDa) increase steadily from the creek mouth to the outer estuary, suggesting that inflowing seawater, rather than AS soil, is the major As source in the estuary. In sediments at the outer estuary, As was accumulated and diagenetically cycled in the surficial layers, as throughout much of the Bothnian Bay. In contrast, in sediments in the inner estuary, As concentrations and accumulation rates showed systematical peaks at greater depths. These peaks were overall consistent with the temporal trend of past As discharges from the Rönnskär smelter and the accompanied As concentrations in past sea-water of the Bothnian Bay, pointing to a connection between the historical smelter activities and the sediment-bound As in the inner estuary. However, the concentrations and accumulation rates of As peaked at depths where the smelter activities had already declined, but a large increase in the deposition of Al hydroxides and Fe phases occurred in response to intensified land-use in the mid 1960's and early 1970's. This correspondence suggests that, apart from the inflowing As-contaminated seawater, capture by Al hydroxides, Fe hydroxides and Fe-organic complexes is another important factor for As deposition in the inner estuary. After accumulating in the sediment, the solid-phase As was partly remobilized, as reflected by increased pore-water As concentrations, a process favored by As(V) reduction and high concentrations of dissolved organic matter. Copyright © 2015 Elsevier B.V. All rights reserved.

Physical-Mechanical Properties and Micromorphology of Calcium Cements Exposed to Polyacrylic and Phosphoric Acids.

PubMed

de Souza, Gustavo Fernandes; Arrais, Ana Beatriz; Aragão, Cícero Flávio Soares; Ferreira, Isana Alvares; Borges, Boniek Castillo Dutra

2018-01-01

To evaluate if physical and mechanical properties of self-curing calcium hydroxide cements were affected by contact with polyacrylic and phosphoric acids. Resin-containing (Life (LF)) and resin-free (Hydro C (HyC)) materials were subjected to polyacrylic acid conditioning and rinsing (POL); phosphoric acid conditioning and rinsing (PHO); rinsing only; and no treatment ( n = 10). Water sorption/solubility, release of hydroxyl ions (pH), roughness (Ra), and impact resistance were evaluated. Additional samples ( n = 1) were prepared for scanning electron microscopy (SEM) analysis of the surface morphology. Data were analyzed by two-way ANOVA and Tukey post hoc test ( P < 0.05). Water sorption was significantly higher for LF when in contact with PHO and lower for POL ( P < 0.05). The mean solubility was higher with POL for both cements ( P < 0.05). PHO increased the mean surface roughness for HyC ( P < 0.01); a significant decrease was noted for LF after contact with both acids ( P < 0.01). PHO promoted lower release of hydroxyl ions on both cements ( P < 0.05). For LF, rinsing, PHO, and POL presented similar morphology, differing from the control group. For HyC, PHO and POL presented similar morphology, differing from the control group. PHO had a negative effect on the physical properties of the cements tested, except for the solubility test. POL affected roughness and solubility of HyC cement. Clinical procedures that require polyacrylic and phosphoric acid conditioning must be done carefully on self-curing calcium hydroxide cements in order to avoid negative impact on their properties.

Addition of a Fluoride-containing Radiopacifier Improves Micromechanical and Biological Characteristics of Modified Calcium Silicate Cements.

PubMed

Antonijevic, Djordje; Jeschke, Anke; Colovic, Bozana; Milovanovic, Petar; Jevremovic, Danimir; Kisic, Danilo; vom Scheidt, Annika; Hahn, Michael; Amling, Michael; Jokanovic, Vukoman; Busse, Björn; Djuric, Marija

2015-12-01

Calcium silicate cements (CSCs) with the addition of nanohydroxyapatite and calcium carbonate play a critical role in dental applications. To further improve their properties, particularly radiopacity and biointeractivity, the fluoride-containing radiopacifier ytterbium trifluoride (YbF3) was added to their composition, and biological and mechanical characteristics were evaluated. YbF3 was added to 3 different CSCs: cement I (CSC + calcium carbonate), cement II (CSC + nanohydroxyapatite), and Portland cement. Material characterization encompassed measurements of pH, calcium, ytterbium, and fluoride ion release; radiopacity; setting time; porosity; microindentation properties; wettability; and Fourier transform infrared spectroscopic, x-ray diffraction, and scanning electron microscopic analyses. Osteoblast- and osteoclast-like cells were grown on the materials' surface to evaluate their adherence. The addition of calcium carbonate, nanohydroxyapatite, and 30 wt% of YbF3 improved radiopacity and the setting time of experimental cements. The pH values did not differ among the groups. The greatest ytterbium and fluoride releases occurred in the Portland cement + YbF3 group. Combined x-ray diffraction and Fourier transform infrared spectroscopic analysis showed the presence of calcium hydroxide and calcium silicate hydrates. In addition, the presence of calcium ytterbium fluoride and ytterbium oxide proved that YbF3 reacted with cement compounds. Wettability of cement I + YbF3 was superior to other formulations, but its porosity and microindentation properties were weaker than in the Portland cement + YbF3 mixture. Cement II + YbF3 presented micromechanical indentation and porosity characteristics similar to the Portland-based cement formulation. Osteoclast- and osteoblast-like cells adhered to the cements' surfaces without alteration of the cell structural integrity. YbF3-containing CSCs with nanostructured hydroxyapatite and calcium carbonate are well suited for

Calcium Orthophosphate-Based Bioceramics

PubMed Central

Dorozhkin, Sergey V.

2013-01-01

Various types of grafts have been traditionally used to restore damaged bones. In the late 1960s, a strong interest was raised in studying ceramics as potential bone grafts due to their biomechanical properties. A bit later, such synthetic biomaterials were called bioceramics. In principle, bioceramics can be prepared from diverse materials but this review is limited to calcium orthophosphate-based formulations only, which possess the specific advantages due to the chemical similarity to mammalian bones and teeth. During the past 40 years, there have been a number of important achievements in this field. Namely, after the initial development of bioceramics that was just tolerated in the physiological environment, an emphasis was shifted towards the formulations able to form direct chemical bonds with the adjacent bones. Afterwards, by the structural and compositional controls, it became possible to choose whether the calcium orthophosphate-based implants remain biologically stable once incorporated into the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of regenerative bioceramics was developed and such formulations became an integrated part of the tissue engineering approach. Now calcium orthophosphate scaffolds are designed to induce bone formation and vascularization. These scaffolds are often porous and harbor different biomolecules and/or cells. Therefore, current biomedical applications of calcium orthophosphate bioceramics include bone augmentations, artificial bone grafts, maxillofacial reconstruction, spinal fusion, periodontal disease repairs and bone fillers after tumor surgery. Perspective future applications comprise drug delivery and tissue engineering purposes because calcium orthophosphates appear to be promising carriers of growth factors, bioactive peptides and various types of cells. PMID:28788309

Process development for production of coal/sorbent agglomerates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapp, D.M.

1991-01-01

The goal of this work was to develop a process flow diagram to economically produce a clean-burning fuel from fine Illinois coal. To accomplish this, the process of pelletizing fine coal with calcium hydroxide, a sulfur capturing sorbent, was investigated. Carbonation, which is the reaction of calcium hydroxide with carbon dioxide (in the presence of moisture) to produce a bonding matrix of calcium carbonate, was investigated as a method for improving pellet quality and reducing binder costs. Proper moisture level is critical to allow the reaction to occur. If too much moisture is present in a pellet, the pore spacesmore » are filled and carbon dioxide must diffuse through the water to reach the calcium hydroxide and react. This severely slows or stops the reaction. The ideal situation is when there is just enough moisture to coat the calcium hydroxide allowing for the reaction to proceed. The process has been successfully demonstrated on a pilot-scale as a method of hardening iron ore pellets (Imperato, 1966). Two potential combustion options are being considered for the coal/calcium hydroxide pellets: fluidized bed combustors and industrial stoker boilers.« less

Process development for production of coal/sorbent agglomerates. Final technical report, September 1, 1990--August 31, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rapp, D.M.

1991-12-31

The goal of this work was to develop a process flow diagram to economically produce a clean-burning fuel from fine Illinois coal. To accomplish this, the process of pelletizing fine coal with calcium hydroxide, a sulfur capturing sorbent, was investigated. Carbonation, which is the reaction of calcium hydroxide with carbon dioxide (in the presence of moisture) to produce a bonding matrix of calcium carbonate, was investigated as a method for improving pellet quality and reducing binder costs. Proper moisture level is critical to allow the reaction to occur. If too much moisture is present in a pellet, the pore spacesmore » are filled and carbon dioxide must diffuse through the water to reach the calcium hydroxide and react. This severely slows or stops the reaction. The ideal situation is when there is just enough moisture to coat the calcium hydroxide allowing for the reaction to proceed. The process has been successfully demonstrated on a pilot-scale as a method of hardening iron ore pellets (Imperato, 1966). Two potential combustion options are being considered for the coal/calcium hydroxide pellets: fluidized bed combustors and industrial stoker boilers.« less

Calcium signaling in neuronal cells exposed to the munitions compound Cyclotrimethylenetrinitramine (RDX).

PubMed

Ehrich, Marion; Wu, Xiaohua; Werre, Stephen R; Major, Michael A; McCain, Wilfred C; Reddy, Gunda

2009-01-01

Cyclotrimethylenetrinitramine (RDX) has been used extensively as an explosive in military munitions. Mechanisms for seizure production, seen in past animal studies, have not been described. Increased calcium levels contribute to excitotoxicity, so in this study neuroblastoma cells are loaded with calcium-indicating dye before application of 1.5 microM to 7.5 mM RDX, with fluorescence recorded for 30 cycles of 11 seconds each. The lowest concentration of RDX increases calcium fluorescence significantly above baseline for cycles 2 to 8; millimolar concentrations increase calcium fluorescence significantly above baseline for cycles 2 to 30. Increases in calcium, like those of 200 nM carbachol, are prevented with 10 mM of calcium chelator ethylene glycol-bis(beta-aminoethyl ether)-N,N,N,N tetra-acetic acid (EGTA, tetrasodium salt). Calcium channel blocker verapamil (20 microM), Ca(2+)-ATPase inhibitor thapsigargin (5 microM), and general membrane stabilizer lidocaine (10 mM) partially attenuate carbachol- and RDX-induced increases in calcium, suggesting that RDX transiently increases intracellular calcium by multiple mechanisms.

Comparative evaluation of antimicrobial efficacy of various root canal filling materials along with aloevera used in primary teeth: a microbiological study.

PubMed

Kriplani, R; Thosar, N; Baliga, M S; Kulkarni, P; Shah, N; Yeluri, R

2013-01-01

this study was conducted to evaluate the antimicrobial effectiveness of 6 root canal filling materials and a negative control agent against 18 strains of bacteria isolated from infected root canals of primary molar teeth using agar diffusion assay. Aloevera with sterile water Zinc oxide and Eugenol, Zinc oxide-Eugenol with aloevera, Calcium hydroxide and sterile water, Calcium hydroxide with sterile water and aloevera, Calcium hydroxide and Iodoform (Metapex) and Vaseline (Control). MIC and MBC of aloevera was calculated. All materials except Vaseline showed varied antimicrobial activity against the test bacterias. The zones of inhibition were ranked into 4 inhibition categories based on the proportional distribution of the data. All the 18 bacterial isolates were classified under 2 groups based on Gram positive and Gram negative aerobes. Statistical analysis was carried out to compare the antimicrobial effectiveness between materials tested with each of the bacterial groupings. Aloevera + Sterile Water was found to have superior antimicrobial activity against most of the microorganisms followed by ZOE + Aloevera, calcium hydroxide + Aloevera, ZOE, calcium hydroxide, Metapex in the descending order and Vaseline showed no inhibition.

Complications of sodium hydroxide chemical matrixectomy: nail dystrophy, allodynia, hyperalgesia.

PubMed

Bostancı, Seher; Koçyiğit, Pelin; Güngör, Hilayda Karakök; Parlak, Nehir

2014-11-01

Ingrown toenails are seen most commonly in young adults, and they can seriously affect daily life. Partial nail avulsion with chemical matrixectomy, generally by using either sodium hydroxide or phenol, is one of the most effective treatment methods. Known complications of phenol matrixectomy are unpredictable tissue damage, prolonged postoperative drainage, increased secondary infection rates, periostitis, and poor cosmetic results. To our knowledge, there have been no reports about the complications related to sodium hydroxide matrixectomy. Herein, we describe three patients who developed nail dystrophy, allodynia, and hyperalgesia after sodium hydroxide matrixectomy.

Method of manufacturing positive nickel hydroxide electrodes

DOEpatents

Gutjahr, M.A.; Schmid, R.; Beccu, K.D.

1975-12-16

A method of manufacturing a positive nickel hydroxide electrode is discussed. A highly porous core structure of organic material having a fibrous or reticular texture is uniformly coated with nickel powder and then subjected to a thermal treatment which provides sintering of the powder coating and removal of the organic core material. A consolidated, porous nickel support structure is thus produced which has substantially the same texture and porosity as the initial core structure. To provide the positive electrode including the active mass, nickel hydroxide is deposited in the pores of the nickel support structure.

Hydroxide catalysts for lignin depolymerization

DOEpatents

Beckham, Gregg T; Biddy, Mary J.; Kruger, Jacob S.; Chmely, Stephen C.; Sturgeon, Matthew

2017-10-17

Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

Hydroxide catalysts for lignin depolymerization

DOEpatents

Beckham, Gregg T.; Biddy, Mary J.; Chmely, Stephen C.; Sturgeon, Matthew

2017-04-25

Solid base catalysts and their use for the base-catalyzed depolymerization (BCD) of lignin to compounds such as aromatics are presented herein. Exemplary catalysts include layered double hydroxides (LDHs) as recyclable, heterogeneous catalysts for BCD of lignin.

Adsorption of arsenic by activated carbon, calcium alginate and their composite beads.

PubMed

Hassan, A F; Abdel-Mohsen, A M; Elhadidy, H

2014-07-01

The present investigation deals with preparation of three different adsorbent materials namely; potassium hydroxide activated carbon based apricot stone (C), calcium alginate beads (G) and calcium alginate/activated carbon composite beads (GC) were used for the removal of arsenic. The prepared adsorbent materials were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), N2-adsorption at -196°C and point of zero charge. From the obtained results, it was found that the porosity, surface area and total pore volume of the adsorbent material C>GC>G respectively, however, the G adsorbent has more acidic function group than the other adsorbents. The influence of pH, time, temperature and initial concentration of arsenic(V) were studied and optimized. GC exhibits the maximum As(V) adsorption (66.7mg/g at 30°C). The adsorption of arsenic ions was observed to follow pseudo-second order mechanism as well as the thermodynamic parameters confirm also the endothermic spontaneous and a physisorption process. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of Curing on the Strength Development of Calcium-Containing Geopolymer Mortar

PubMed Central

Li, Xueying; Wang, Zheng; Jiao, Zhenzhen

2013-01-01

This paper investigated the curing effects on the mechanical properties of calcium-containing geopolymer mortar. Three precursors are used: Class C fly ash, Class F fly ash plus calcium hydroxide and Class F fly ash plus slag. Curing conditions included: (1) standard curing at 20 ± 3 °C and RH 95% (C); (2) steam curing at 60 °C for 24 h (S); (3) steam curing at 60 °C for 6 h (S6); and (4) oven curing at 60 °C for 24 h (O), then the latter three followed by the standard curing. Under the standard conditions, the flexural strength and compressive strength of Class C fly ash geopolymer mortars developed quickly until the age of 7 days, followed by a gradual increase. Specimens with Class F fly ash plus Ca(OH)2 showed slow increase till the age of 28 days. Under these non-standard conditions (2–4), all specimens showed higher 3-day strength, while later strengths were either higher or lower than those in standard conditions, depending on the type of the precursor. PMID:28788377

Influence of Curing on the Strength Development of Calcium-Containing Geopolymer Mortar.

PubMed

Li, Xueying; Wang, Zheng; Jiao, Zhenzhen

2013-11-07

This paper investigated the curing effects on the mechanical properties of calcium-containing geopolymer mortar. Three precursors are used: Class C fly ash, Class F fly ash plus calcium hydroxide and Class F fly ash plus slag. Curing conditions included: (1) standard curing at 20 ± 3 °C and RH 95% (C); (2) steam curing at 60 °C for 24 h (S); (3) steam curing at 60 °C for 6 h (S6); and (4) oven curing at 60 °C for 24 h (O), then the latter three followed by the standard curing. Under the standard conditions, the flexural strength and compressive strength of Class C fly ash geopolymer mortars developed quickly until the age of 7 days, followed by a gradual increase. Specimens with Class F fly ash plus Ca(OH)₂ showed slow increase till the age of 28 days. Under these non-standard conditions (2-4), all specimens showed higher 3-day strength, while later strengths were either higher or lower than those in standard conditions, depending on the type of the precursor.

Method of treating inflammatory diseases using a radiolabeled ferric hydroxide calloid

DOEpatents

Atcher, Robert W.; Hines, John J.

1992-01-01

A ferric hydroxide colloid having an alpha-emitting radionuclide essentially on the outer surfaces and a method of forming same. The method includes oxidizing a ferrous hydroxide to ferric hydroxide in the presence of a preselected radionuclide to form a colloid having the radionuclide on the outer surface thereof, and thereafter washing the colloid, and suspending the washed colloid in a suitable solution. The labelled colloid is useful in cancer therapy and for the treatment of inflamed joints.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin.

PubMed

Dainezi, Vanessa Benetello; Iwamoto, Alexsandra Shizue; Martin, Airton Abrahão; Soares, Luís Eduardo Silva; Hosoya, Yumiko; Pascon, Fernanda Miori; Puppin-Rontani, Regina Maria

2017-01-01

This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules.

Rapeseed-straw enzymatic digestibility enhancement by sodium hydroxide treatment under ultrasound irradiation.

PubMed

Kang, Kyeong Eop; Jeong, Gwi-Taek; Park, Don-Hee

2013-08-01

In this study, we carried out sodium hydroxide and sonication pretreatments of rapeseed straw (Brassica napus) to obtain monosugar suitable for production of biofuels. To optimize the pretreatment conditions, we applied a statistical response-surface methodology. The optimal pretreatment conditions using sodium hydroxide under sonication irradiation were determined to be 75.0 °C, 7.0 % sodium hydroxide, and 6.8 h. For these conditions, we predicted 97.3 % enzymatic digestibility. In repeated experiments to validate the predicted value, 98.9 ± 0.3 % enzymatic digestibility was obtained, which was well within the range of the predicted model. Moreover, sonication irradiation was found to have a good effect on pretreatment in the lower temperature range and at all concentrations of sodium hydroxide. According to scanning electron microscopy images, the surface area and pore size of the pretreated rapeseed straw were modified by the sodium hydroxide pretreatment under sonication irradiation.

Controllable synthesis of layered Co-Ni hydroxide hierarchical structures for high-performance hybrid supercapacitors

NASA Astrophysics Data System (ADS)

Yuan, Peng; Zhang, Ning; Zhang, Dan; Liu, Tao; Chen, Limiao; Ma, Renzhi; Qiu, Guanzhou; Liu, Xiaohe

2016-01-01

A facile solvothermal method is developed for synthesizing layered Co-Ni hydroxide hierarchical structures by using hexamethylenetetramine (HMT) as alkaline reagent. The electrochemical measurements reveal that the specific capacitances of layered bimetallic (Co-Ni) hydroxides are generally superior to those of layered monometallic (Co, Ni) hydroxides. The as-prepared Co0.5Ni0.5 hydroxide hierarchical structures possesses the highest specific capacitance of 1767 F g-1 at a galvanic current density of 1 A g-1 and an outstanding specific capacitance retention of 87% after 1000 cycles. In comparison with the dispersed nanosheets of Co-Ni hydroxide, layered hydroxide hierarchical structures show much superior electrochemical performance. This study provides a promising method to construct hierarchical structures with controllable transition-metal compositions for enhancing the electrochemical performance in hybrid supercapacitors.

Synthesis of high capacity cathodes for lithium-ion batteries by morphology-tailored hydroxide co-precipitation

NASA Astrophysics Data System (ADS)

Wang, Dapeng; Belharouak, Ilias; Ortega, Luis H.; Zhang, Xiaofeng; Xu, Rui; Zhou, Dehua; Zhou, Guangwen; Amine, Khalil

2015-01-01

Nickel manganese hydroxide co-precipitation inside a continuous stirred tank reactor was studied with sodium hydroxide and ammonium hydroxide as the precipitation agents. The ammonium hydroxide concentration had an effect on the primary and secondary particle evolution. The two-step precipitation mechanism proposed earlier was experimentally confirmed. In cell tests, Li- and Mn-rich composite cathode materials based on the hydroxide precursors demonstrated good electrochemical performance in terms of cycle life over a wide range of lithium content.

Comparison of phenol and sodium hydroxide chemical matricectomies for the treatment of ingrowing toenails.

PubMed

Bostanci, Seher; Kocyigit, Pelin; Gürgey, Erbak

2007-06-01

Chemical matricectomy is performed mainly by two agents: phenol and sodium hydroxide. Both agents have excellent cure rates, but there are no data about the comparison of postoperative healing periods. This study was designed to compare the postoperative morbidity rates of sodium hydroxide and phenol matricectomies. Forty-six patients with 154 ingrowing nail sides were treated with either sodium hydroxide or phenol matricectomy. In the postoperative period, the patients were evaluated for the duration and severity of pain, drainage, and peripheral tissue destruction; complete healing periods; and overall success rates. The incidence of pain was higher in the sodium hydroxide group on the first visit, on the second day, but all patients became pain-free after that. The incidence and duration of drainage and peripheral tissue destruction was significantly higher in the phenol group. The mean period for complete recovery was 10.8 days in the sodium hydroxide group, whereas it was 18.02 days in the phenol group. The overall success rates in the sodium hydroxide and phenol groups were found to be 95.1 and 95.8%, respectively. Both sodium hydroxide and phenol are effective agents giving high success rates, but sodium hydroxide causes less postoperative morbidity and provides faster recovery.

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition

PubMed Central

Nakayama, Hirokazu; Hayashi, Aki

2014-01-01

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids. PMID:25080007

Mixing Acid Salts and Layered Double Hydroxides in Nanoscale under Solid Condition.

PubMed

Nakayama, Hirokazu; Hayashi, Aki

2014-07-30

The immobilization of potassium sorbate, potassium aspartate and sorbic acid in layered double hydroxide under solid condition was examined. By simply mixing two solids, immobilization of sorbate and aspartate in the interlayer space of nitrate-type layered double hydroxide, so called intercalation reaction, was achieved, and the uptakes, that is, the amount of immobilized salts and the interlayer distances of intercalation compounds were almost the same as those obtained in aqueous solution. However, no intercalation was achieved for sorbic acid. Although intercalation of sorbate and aspartate into chloride-type layered double hydroxide was possible, the uptakes for these intercalation compounds were lower than those obtained using nitrate-type layered double hydroxide. The intercalation under solid condition could be achieved to the same extent as for ion-exchange reaction in aqueous solution, and the reactivity was similar to that observed in aqueous solution. This method will enable the encapsulation of acidic drug in layered double hydroxide as nano level simply by mixing both solids.

Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application

NASA Astrophysics Data System (ADS)

Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

2017-03-01

Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co0.54Fe0.46OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co0.54Fe0.46OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

Effective Construction of High-quality Iron Oxy-hydroxides and Co-doped Iron Oxy-hydroxides Nanostructures: Towards the Promising Oxygen Evolution Reaction Application.

PubMed

Zhang, Xinyu; An, Li; Yin, Jie; Xi, Pinxian; Zheng, Zhiping; Du, Yaping

2017-03-08

Rational design of high efficient and low cost electrocatalysts for oxygen evolution reaction (OER) plays an important role in water splitting. Herein, a general gelatin-assisted wet chemistry method is employed to fabricate well-defined iron oxy-hydroxides and transitional metal doped iron oxy-hydroxides nanomaterials, which show good catalytic performances for OER. Specifically, the Co-doped iron oxy-hydroxides (Co 0.54 Fe 0.46 OOH) show the excellent electrocatalytic performance for OER with an onset potential of 1.52 V, tafel slope of 47 mV/dec and outstanding stability. The ultrahigh oxygen evolution activity and strong durability, with superior performance in comparison to the pure iron oxy-hydroxide (FeOOH) catalysts, originate from the branch structure of Co 0.54 Fe 0.46 OOH on its surface so as to provide many active edge sites, enhanced mass/charge transport capability, easy release oxygen gas bubbles, and strong structural stability, which are advantageous for OER. Meanwhile, Co-doping in FeOOH nanostructures constitutes a desirable four-electron pathway for reversible oxygen evolution and reduction, which is potentially useful for rechargeable metal-air batteries, regenerative fuel cells, and other important clean energy devices. This work may provide a new insight into constructing the promising water oxidation catalysts for practical clean energy application.

Calcium metaborate as a cathode additive to improve the high-temperature properties of nickel hydroxide electrodes for nickel-metal hydride batteries

NASA Astrophysics Data System (ADS)

Li, Jing; Shangguan, Enbo; Guo, Dan; Li, Quanmin; Chang, Zhaorong; Yuan, Xiao-Zi; Wang, Haijiang

2014-10-01

In this paper, a novel additive, calcium metaborate (CMB), is proposed to improve the high-temperature characteristics of the nickel electrodes for nickel-metal hydride batteries. As a soluble calcium salt, CMB can easily and uniformly be dispersed in the nickel electrodes. The effects of CMB on the nickel electrode are investigated via a combination of cyclability, capacity retention, electrochemical impedance spectroscopy, scanning electron microscope and X-ray diffraction. Compared with conventional nickel electrodes, the electrode containing 0.5 wt.% CMB exhibits superior electrode properties including enhanced discharge capacity, improved high-rate discharge ability and excellent cycle stability at an elevated temperature (70 °C). The improved cell performance of the nickel electrode containing CMB additives can be attributable to the increased oxygen evolution overvoltage and slower oxygen evolution rate. Compared with insoluble calcium salts, such as Ca(OH)2, CaCO3, and CaF2, CMB is more effective as a cathode additive to improve the high-temperature performance of Ni-MH batteries.

Calcium bioavailability and kinetics of calcium ascorbate and calcium acetate in rats.

PubMed

Cai, Jianwei; Zhang, Qinmin; Wastney, Meryl E; Weaver, Connie M

2004-01-01

The objective was to investigate the bioavailability and mechanism of calcium absorption of calcium ascorbate (ASC) and calcium acetate (AC). A series of studies was performed in adult Sprague-Dawley male rats. In the first study, each group of rats (n = 10/group) was assigned to one of the five test meals labeled with (45)Ca: (i) 25 mg calcium as heated ASC or (ii) unheated ASC, (iii) 25 mg calcium as unheated AC, (iv) 3.6 mg Ca as unheated ASC, or (v) unheated AC. Femur uptake indicated better calcium bioavailability from ASC than AC at both calcium loads. A 5-min heat treatment partly reduced bioavailability of ASC. Kinetic studies were performed to further investigate the mechanism of superior calcium bioavailability from ASC. Two groups of rats (n = 10/group) received oral doses of 25 mg Ca as ASC or AC. Each dose contained 20 micro Ci (45)Ca. Two additional groups of rats (n = 10/group) received an intravenous injection (iv) of 10 micro Ci (45)Ca after receiving an unlabeled oral dose of 25 mg calcium as ASC or AC. Sequential blood samples were collected over 48 hrs. Urine and fecal samples were collected every 12 hrs for 48 hrs and were analyzed for total calcium and (45)Ca content. Total calcium and (45)Ca from serum, urine, and feces were fitted by a compartment kinetics model with saturable and nonsaturable absorption pathways by WinSAAM (Windows-based Simulation Analysis and Modeling). The difference in calcium bioavailability between the two salts was due to differences in saturable rather than passive intestinal absorption and not to endogenous secretion or calcium deposition rate. The higher bioavailability of calcium ascorbate was due to a longer transit time in the small intestine compared with ASC.

Hydroxide ion-mediated synthesis of monodisperse dopamine-melanin nanospheres.

PubMed

Cho, Soojeong; Kim, Shin-Hyun

2015-11-15

Dopamine-melanin nanospheres are promising materials for photoprotection, structural coloration, and thermoregulation due to their unusual optical and chemical properties. Here, we report the experimental parameters which influence size of dopamine-melanin nanospheres and uniformity. Dopamine precursors are oxidatively polymerized in basic aqueous medium. Therefore, concentration of hydroxide ions significantly influences reaction rate and size of nanospheres. To investigate the effect of hydroxide ions, we adjust three different parameters which affect pH of medium: concentration of sodium hydroxide and dopamine hydrochloride, and reaction temperature. At constant temperature, concentration of hydroxide ions is linearly proportional to initial reaction rates which determine the number of nuclei for nanosphere growth. Temperature alters not only initial reaction rate but also diffusivity of molecules, leading to deviation from the relation between the reaction rate and the number of nuclei. The diameter of dopamine-melanin nanospheres can be readily controlled in a range of 80-490nm through adjusting concentration of dopamine precursor, while maintaining uniform-size distribution and dispersion stability. The synthesized nanospheres are analyzed to confirm the chemical structure, which is composed of approximately 6 indole units. Moreover, surface and chemical properties of the nanospheres are characterized to provide valuable information for surface modification and application. Copyright © 2015 Elsevier Inc. All rights reserved.

Sodium hydroxide catalyzed monodispersed high surface area silica nanoparticles.

PubMed

Bhakta, Snehasis; Dixit, Chandra K; Bist, Itti; Jalil, Karim Abdel; Suib, Steven L; Rusling, James F

2016-07-01

Understanding of the synthesis kinetics and our ability to modulate medium conditions allowed us to generate nanoparticles via an ultra-fast process. The synthesis medium is kept quite simple with tetraethyl orthosilicate (TEOS) as precursor and 50% ethanol and sodium hydroxide catalyst. Synthesis is performed under gentle conditions at 20 °C for 20 min Long synthesis time and catalyst-associated drawbacks are most crucial in silica nanoparticle synthesis. We have addressed both these bottlenecks by replacing the conventional Stober catalyst, ammonium hydroxide, with sodium hydroxide. We have reduced the overall synthesis time from 20 to 1/3 h, ~60-fold decrease, and obtained highly monodispersed nanoparticles with 5-fold higher surface area than Stober particles. We have demonstrated that the developed NPs with ~3-fold higher silane can be used as efficient probes for biosensor applications.

Vibrational dynamics of aqueous hydroxide solutions probed using broadband 2DIR spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mandal, Aritra; Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139; Tokmakoff, Andrei, E-mail: tokmakoff@uchicago.edu

2015-11-21

We employed ultrafast transient absorption and broadband 2DIR spectroscopy to study the vibrational dynamics of aqueous hydroxide solutions by exciting the O–H stretch vibrations of the strongly hydrogen-bonded hydroxide solvation shell water and probing the continuum absorption of the solvated ion between 1500 and 3800 cm{sup −1}. We observe rapid vibrational relaxation processes on 150–250 fs time scales across the entire probed spectral region as well as slower vibrational dynamics on 1–2 ps time scales. Furthermore, the O–H stretch excitation loses its frequency memory in 180 fs, and vibrational energy exchange between bulk-like water vibrations and hydroxide-associated water vibrations occursmore » in ∼200 fs. The fast dynamics in this system originate in strong nonlinear coupling between intra- and intermolecular vibrations and are explained in terms of non-adiabatic vibrational relaxation. These measurements indicate that the vibrational dynamics of the aqueous hydroxide complex are faster than the time scales reported for long-range transport of protons in aqueous hydroxide solutions.« less

Mechanisms of mineral membrane fouling growth modulated by pulsed modes of current during electrodialysis: evidences of water splitting implications in the appearance of the amorphous phases of magnesium hydroxide and calcium carbonate.

PubMed

Cifuentes-Araya, Nicolás; Astudillo-Castro, Carolina; Bazinet, Laurent

2014-07-15

Experiments revealed the fouling nature evolutions along different electrodialysis (ED) trials, and how it disappears when current pulsation acts repetitively on the interfaces of ion-exchange membranes (IEMs). Fouling was totally controlled on the diluate side of cation-exchange membrane (CEM) by the repetitive pulsation frequency of the higher on-duty ratios applied. They created steady water splitting proton-barriers that neutralized OH(-) leakage through the membrane, decreasing the interfacial pH, and fouling of the concentrate side. The anion-exchange membrane (AEM) on the diluate side was similarly protected, but it was fouled once water splitting OH(-) generation became either intense enough or excessively weak. Interestingly, amorphous magnesium hydroxide (AMH) stemmed on the CEM-diluate side from brucite under intense water splitting OH(-) generation, and/or strong OH(-) leakage electromigration through the membrane. Water dissociation and overlimiting current regimes triggered drastic water molecule removal from crystal lattices through an accelerated cascade water splitting reaction. Also, amorphous calcium carbonate (ACC) appeared on CEM under intense water splitting reaction, and disappeared once intense OH(-) leakage was allowed by the water splitting proton-barrier dissipation. Our findings have implications for membrane fouling control, as well as for the understanding of the growth behavior of CaCO3 and Mg(OH)2 species on electromembrane interfaces. Copyright © 2014 Elsevier Inc. All rights reserved.

Clogging and Cementation Caused by Calcium or Iron Biogrouts

NASA Astrophysics Data System (ADS)

Ivanov, V.; Chu, J.; Naeimi, M.

2012-12-01

Chemical grouts are often used to reduce the hydraulic conductivity of soil for seepage control purposes. However, chemical grouts can be expensive and environmentally unfriendly. Therefore, two new biogrouts were tested for their bioclogging and biocementation properties. The first was calcium-based biogrout, which contained urease-producing bacteria, calcium chloride and urea for the crystallization of calcite due to enzymatic hydrolysis of urea. The second was iron-based biogrout, which consisted of urease-producing bacteria, ferric chelate, and urea for the precipitation of ferric hydroxide and carbonate due to enzymatic hydrolysis of urea. The permeability of sand (P, 10^-5 m/s), treated with calcium-based biogrout, linearly decreased as a function of the content of precipitated calcium (C, % w/w) according to the following equation: P = 5.1 - 4.0 C. Meanwhile, the permeability of sand treated with iron-based biogrout dropped to 2.7x10^-6 m/s at content of precipitated iron (F, % w/w) about 0.35 % w/w , by the equation: P = 5.1 - 14.6 F , and then slowly decreased to 1.4x10^-7 m/s at content of precipitated iron 1.8% w/w by the following equation: P = 0.36 - 0.23F. Both biogrouts have approximately same efficiency in the reduction of permeability of sand to low values. However, the mechanisms of bioclogging are probably different because the reduction of permeability by calcium-based biogrout was described by linear function of precipitated calcium but the reduction of permeability by iron-based biogrout showed two steps of the clogging. Different functions and mechanisms were related probably to the different type of precipitates. The images of biogrouted sand samples show that calcium-based biogrout produced white amorphous or crystallised calcium carbonate, while iron-based biogrout produced gel-like brown precipitate without visible crystals. The unconfined compressive strengths of the sand treated with different biogrouts (Y, kPa) increased by power

The increased risk of urinary stone disease in betel quid chewers.

PubMed

Allen, Siân E; Singh, Sadmeet; Robertson, William G

2006-08-01

The chewing of betel quid is a common practice in many countries of the world, particularly in Southeast Asia. The quid consists of a preparation of areca nut, betel leaf and calcium hydroxide "lime" paste ("chuna"). For the first time, we present a study that links its use to urinary stone disease. Eight patients (seven male and one female) who presented to our Stone Unit with recurrent urinary stones were included in the study. All were from the Indian subcontinent and were found to regularly chew betel. The patients underwent metabolic screening including blood, random urine and 24-h urine tests, quantitative chemical analysis of their calculi (where possible) and each completed a 7-day Diet Diary on his/her free, home diet. The study demonstrated a high incidence of hypercalciuria, a tendency to pass an alkaline urine and low urinary citrate excretion among the patients. Together these urinary risk factors increase the probability of developing both calcium phosphate-containing and calcium oxalate-containing stones. In support of this hypothesis, the patients were found to form stones consisting mainly of calcium phosphate but mixed with calcium oxalate. It is concluded that the use of calcium hydroxide "chuna" in the betel quid is the major contributor to the cause of urinary stones in its users. Moreover, the development of urinary lithiasis in such patients may be a precursor to milk-alkali syndrome in those individuals whose chewing habit is more extensive than in the patients in this study and who do not seek to decrease their habit over the long term.

Safety Assessment of Alumina and Aluminum Hydroxide as Used in Cosmetics.

PubMed

Becker, Lillian C; Boyer, Ivan; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

2016-11-01

This is a safety assessment of alumina and aluminum hydroxide as used in cosmetics. Alumina functions as an abrasive, absorbent, anticaking agent, bulking agent, and opacifying agent. Aluminum hydroxide functions as a buffering agent, corrosion inhibitor, and pH adjuster. The Food and Drug Administration (FDA) evaluated the safe use of alumina in several medical devices and aluminum hydroxide in over-the-counter drugs, which included a review of human and animal safety data. The Cosmetic Ingredient Review (CIR) Expert Panel considered the FDA evaluations as part of the basis for determining the safety of these ingredients as used in cosmetics. Alumina used in cosmetics is essentially the same as that used in medical devices. This safety assessment does not include metallic or elemental aluminum as a cosmetic ingredient. The CIR Expert Panel concluded that alumina and aluminum hydroxide are safe in the present practices of use and concentration described in this safety assessment. © The Author(s) 2016.

Preeminent productivity of 1,3-propanediol by Clostridium butyricum JKT37 and the role of using calcium carbonate as pH neutraliser in glycerol fermentation.

PubMed

Tee, Zhao Kang; Jahim, Jamaliah Md; Tan, Jian Ping; Kim, Byung Hong

2017-06-01

Calcium carbonate was evaluated as a replacement for the base during the fermentation of glycerol by a highly productive strain of 1,3-propanediol (PDO), viz., Clostridium butyricum JKT37. Due to its high specific growth rate (µ max =0.53h -1 ), 40g/L of glycerol was completely converted into 19.6g/L of PDO in merely 7h of batch fermentation, leaving only acetate and butyrate as the by-products. The accumulation of these volatile fatty acids was circumvented with the addition of calcium carbonate as the pH neutraliser before the fermentation was inoculated. An optimal amount of 15g/L of calcium carbonate was statistically determined from screening with various glycerol concentrations (20-120g/L). By substituting potassium hydroxide with calcium carbonate as the pH neutraliser for fermentation in a bioreactor, a similar yield (Y PDO/glycerol =0.6mol/mol) with a constant pH was achieved at the end of the fermentation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Early Age Carbonation Heat and Products of Tricalcium Silicate Paste Subject to Carbon Dioxide Curing.

PubMed

Li, Zhen; He, Zhen; Shao, Yixin

2018-05-04

This paper presents a study on the carbonation reaction heat and products of tricalcium silicate (C₃S) paste exposed to carbon dioxide (CO₂) for rapid curing. Reaction heat was measured using a retrofitted micro-calorimeter. The highest heat flow of a C₃S paste subject to carbonation curing was 200 times higher than that by hydration, and the cumulative heat released by carbonation was three times higher. The compressive strength of a C₃S paste carbonated for 2 h and 24 h was 27.5 MPa and 62.9 MPa, respectively. The 24-h carbonation strength had exceeded the hydration strength at 28 days. The CO₂ uptake of a C₃S paste carbonated for 2 h and 24 h was 17% and 26%, respectively. The X-ray diffraction (XRD), transmission electron microscope coupled with energy dispersive spectrometer (TEM-EDS), and 29 Si magic angle spinning⁻nuclear magnetic resonance ( 29 Si MAS-NMR) results showed that the products of a carbonated C₃S paste were amorphous silica (SiO₂) and calcite crystal. There was no trace of calcium silicate hydrate (C⁻S⁻H) or other polymorphs of calcium carbonate (CaCO₃) detected.

Sodium hydroxide permethylation of heparin disaccharides.

PubMed

Heiss, Christian; Wang, Zhirui; Azadi, Parastoo

2011-03-30

Permethylation is a valuable and widely used tool for the mass spectrometry of carbohydrates, improving sensitivity and fragmentation and increasing the amount of information that can be obtained from tandem mass spectrometric experiments. Permethylation of most glycans is easily performed with sodium hydroxide and iodomethane in dimethyl sulfoxide (DMSO). However, permethylation has not been widely used in the mass spectrometry of glycosaminoglycan (GAG) oligosaccharides, partly because it has required the use of the difficult Hakomori method employing the methylsulfinylmethanide ('dimsyl') base, which has to be made in a tedious process. Additionally, the Hakomori method is not as effective as the sodium hydroxide method in making fully methylated derivatives. A further problem in the permethylation of highly sulfated oligosaccharides is their limited solubility in DMSO. This paper describes the use of the triethylammonium counterion to overcome this problem, as well as the application of the sodium hydroxide method to make permethylated heparin disaccharides and their workup to yield fully methylated disaccharides for electrospray ionization mass spectrometry. The ease, speed, and effectiveness of the described methodology should open up permethylation of GAG oligosaccharides to a wider circle of mass spectrometrists and enable them to develop further derivatization schemes in the effort to rapidly elucidate the structure of these important molecules. Permethylation may also provide new ways of separating GAG oligosaccharides in LC/MS, their increased hydrophobicity making them amenable for reversed-phase chromatography without the need for ion pairing reagents. Copyright © 2011 John Wiley & Sons, Ltd.

Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia

PubMed Central

Wilson, Rosamund J; Copley, J Brian

2017-01-01

Background Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. Scope A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Findings Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Conclusion Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance. PMID:28182142

Calcium sulfoaluminate (Ye'elimite) hydration in the presence of gypsum, calcite, and vaterite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hargis, Craig W.; Telesca, Antonio; Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu

Six calcium sulfoaluminate-based cementitious systems composed of calcium sulfoaluminate, calcite, vaterite, and gypsum were cured as pastes and mortars for 1, 7, 28 and 84 days. Pastes were analyzed with X-ray diffraction, thermogravimetric and differential thermal analyses. Mortars were tested for compressive strength, dimensional stability and setting time. Furthermore, pastes with a water/cementitious material mass ratio of 0.80 were tested for heat evolution during the first 48 h by means of isothermal conduction calorimetry. It has been found that: (1) both calcite and vaterite reacted with monosulfoaluminate to give monocarboaluminate and ettringite, with vaterite being more reactive; (2) gypsum loweredmore » the reactivity of both carbonates; (3) expansion was reduced by calcite and vaterite, irrespective of the presence of gypsum; and (4) both carbonates increased compressive strength in the absence of gypsum and decreased compressive strength less in the presence of gypsum, with vaterite's action more effective than that of calcite.« less

Calcium sulfoaluminate cement blended with OPC: A potential binder to encapsulate low-level radioactive slurries of complex chemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cau Dit Coumes, Celine; Courtois, Simone; Peysson, Sandrine

Investigations were carried out in order to solidify in cement a low-level radioactive waste of complex chemistry obtained by mixing two process streams, a slurry produced by ultra-filtration and an evaporator concentrate with a salinity of 600 gxL{sup -1}. Direct cementation with Portland cement (OPC) was not possible due to a very long setting time of cement resulting from borates and phosphates contained in the waste. According to a classical approach, this difficulty could be solved by pre-treating the waste to reduce adverse cement-waste interactions. A two-stage process was defined, including precipitation of phosphates and sulfates at 60 deg. Cmore » by adding calcium and barium hydroxide to the waste stream, and encapsulation with a blend of OPC and calcium aluminate cement (CAC) to convert borates into calcium quadriboroaluminate. The material obtained with a 30% waste loading complied with specifications. However, the pre-treatment step made the process complex and costly. A new alternative was then developed: the direct encapsulation of the waste with a blend of OPC and calcium sulfoaluminate cement (CSA) at room temperature. Setting inhibition was suppressed, which probably resulted from the fact that, when hydrating, CSA cement formed significant amounts of ettringite and calcium monosulfoaluminate hydrate which incorporated borates into their structure. As a consequence, the waste loading could be increased to 56% while keeping acceptable properties at the laboratory scale.« less

The high-pressure phase transitions of hydroxides

NASA Astrophysics Data System (ADS)

Nishi, M.; Kuwayama, Y.; Tsuchiya, J.; Tsuchiya, T.; Irifune, T.

2017-12-01

The discovery of new high-pressure hydrous minerals has important implications for understanding the structure, dynamics, and evolution of the Earth, since hydrogen significantly affects the physical properties and stabilities of Earth's constituent minerals. Whereas hydrous minerals commonly dehydrate under pressures of around a few tens of gigapascals (GPa) and at temperature around 1,500 K, those with CaCl2-type crystal structure, MgSiO4H2 phase H, δ-AlOOH and ɛ-FeOOH, are known to be stable at pressures corresponding to the lower mantle. However, although the CaCl2-type hydroxides were suggested to form a solid solution owing to their similar crystal structure, there are few experimental studies on the stability of the hydroxide in such multicomponent. Moreover, ab initio calculations have predicted that some CaCl2-type hydroxides transform to pyrite-type structure at higher pressures. Here, we conducted high pressure-temperature experiments on pure AlOOH, FeOOH, and their solid solutions, with the aid of these first-principles predictions. We use in situ X-ray measurements in conjunction with a multi-anvil apparatus to study the high-pressure behaviour of hydroxides in the multicomponent system under middle lower mantle conditions. Solid solutions in wide compositional ranges between CaCl2-type δ-AlOOH and ɛ-FeOOH were recognized from X-ray diffraction patterns. Also, unit cell volume of FeOOH and (Al,Fe)OOH significantly decreased accompanied with the spin transition of iron at 50 GPa. Thus, the wide compositional ranges in CaCl2-type hydroxide are maintained beyond the depth of the middle lower mantle, where the spin transition of iron occurs. We used a laser-heated diamond anvil cell in order to study the stability of AlOOH and FeOOH at higher pressures above 70 GPa. We observed that ɛ-FeOOH transforms to the pyrite-type structure at above 80 GPa, which is consistent with the theoretical prediction. At conditions above 190 GPa and 2,500 K, we observed

The effect of polymers onto the size of zinc layered hydroxide salt and its calcined product

NASA Astrophysics Data System (ADS)

Hussein, Mohd Zobir bin; Ghotbi, Mohammad Yeganeh; Yahaya, Asmah Hj; Abd Rahman, Mohd Zaki

2009-02-01

Zinc hydroxide nitrate, a brucite-like layered material was synthesized using pH control method. Poly(vinyl alcohol) and poly(ethylene glycol) were used at various percentages as size decreasing agents during the synthesis of zinc hydroxide nitrate. SEM and PXRD showed the decrease of size and thickness of the resultant zinc hydroxide nitrates. TG and surface area data confirmed the decrease of the particle sizes, too. When zinc hydroxide nitrates were heat treated at 500 °C, the physical properties of nano zinc oxides obtained depended on the parent material, zinc hydroxide nitrate.

Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

PubMed Central

Mamillapalli, Ramanaiah; VanHouten, Joshua; Dann, Pamela; Bikle, Daniel; Chang, Wenhan; Brown, Edward

2013-01-01

To meet the demands for milk calcium, the lactating mother adjusts systemic calcium and bone metabolism by increasing dietary calcium intake, increasing bone resorption, and reducing renal calcium excretion. As part of this adaptation, the lactating mammary gland secretes PTHrP into the maternal circulation to increase bone turnover and mobilize skeletal calcium stores. Previous data have suggested that, during lactation, the breast relies on the calcium-sensing receptor (CaSR) to coordinate PTHrP secretion and milk calcium transport with calcium availability. To test this idea genetically, we bred BLG-Cre mice with CaSR-floxed mice to ablate the CaSR specifically from mammary epithelial cells only at the onset of lactation (CaSR-cKO mice). Loss of the CaSR in the lactating mammary gland did not disrupt alveolar differentiation or milk production. However, it did increase the secretion of PTHrP into milk and decreased the transport of calcium from the circulation into milk. CaSR-cKO mice did not show accelerated bone resorption, but they did have a decrease in bone formation. Loss of the mammary gland CaSR resulted in hypercalcemia, decreased PTH secretion, and increased renal calcium excretion in lactating mothers. Finally, loss of the mammary gland CaSR resulted in decreased calcium accrual by suckling neonates, likely due to the combination of increased milk PTHrP and decreased milk calcium. These results demonstrate that the mammary gland CaSR coordinates maternal bone and calcium metabolism, calcium transport into milk, and neonatal calcium accrual during lactation. PMID:23782944

PROCESS FOR SEPARATING PLUTONIUM BY REPEATED PRECIPITATION WITH AMPHOTERIC HYDROXIDE CARRIERS

DOEpatents

Faris, B.F.

1960-04-01

A multiple carrier precipitation method is described for separating and recovering plutonium from an aqueous solution. The hydroxide of an amphoteric metal is precipitated in an aqueous plutonium-containing solution. This precipitate, which carries plutonium, is then separated from the supernatant liquid and dissolved in an aqueous hydroxide solution, forming a second plutonium- containing solution. lons of an amphoteric metal which forms an insoluble hydroxide under the conditions existing in this second solution are added to the second solution. The precipitate which forms and which carries plutonium is separated from the supernatant liquid. Amphoteric metals which may be employed are aluminum, bibmuth, copper, cobalt, iron, lanthanum, nickel, and zirconium.

Role of calcium on chloride binding in hydrated Portland cement–metakaolin–limestone blends

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Zhenguo; Geiker, Mette Rica; De Weerdt, Klaartje

Chloride binding is investigated for Portland cement–metakaolin–limestone pastes exposed to CaCl{sub 2} and NaCl solutions. The phase assemblages and the amount of Friedel's salt are evaluated using TGA, XRD and thermodynamic modeling. A larger amount of Friedel's salt is observed in the metakaolin blends compared to the pure Portland cement. A higher total chloride binding is observed for the pastes exposed to the CaCl{sub 2} solution relative to those in the NaCl solution. This is reflected by the fact that calcium increases the quantity of Friedel's salt in the metakaolin blends by promoting the transformation of strätlingite and/or monocarbonate tomore » Friedel's salt. Calcium increases also the amount of chloride in the diffuse layer of the C-S-H for the pure cement. A linear correlation between the total bound chloride and the uptake of calcium from the CaCl{sub 2} solution is obtained and found to be independent on the type of cement blend.« less

Detection of interstellar sodium hydroxide in self-absorption toward the galactic center

NASA Technical Reports Server (NTRS)

Hollis, J. M.; Rhodes, P. J.

1982-01-01

A weak self-absorbed emission line, which is identified as the J = 4-3 transition of sodium hydroxide, has been detected in the direction of Sgr B2(OH). The correspondingly weak Sgr B2(QH) emission line U75406, previously reported as an unidentified spectral feature by other investigators, is consistent with the J = 3-2 transition of sodium hydroxide. This detection may represent the first evidence of a grain reaction formation mechanism for simple metal hydroxides. The detection of H62 Delta toward Orion A is also reported.

Molecular and morphological surface analysis: effect of filling pastes and cleaning agents on root dentin

PubMed Central

DAINEZI, Vanessa Benetello; IWAMOTO, Alexsandra Shizue; MARTIN, Airton Abrahão; SOARES, Luís Eduardo Silva; HOSOYA, Yumiko; PASCON, Fernanda Miori; PUPPIN-RONTANI, Regina Maria

2017-01-01

Abstract The quality of the dentin root is the most important factor for restoration resin sealing and drives the outcome of endodontic treatment. Objective This study evaluated the effect of different filling pastes and cleaning agents on the root dentin of primary teeth using Fourier-transformed Raman spectroscopy (FT-Raman), micro energy-dispersive X-ray fluorescence (µ-EDXRF) and scanning electron microscopic (SEM) analysis. Material and Methods Eighty roots of primary teeth were endodontically prepared and distributed into 4 groups and filled according to the following filling pastes: Control-no filling (CP), Calen®+zinc oxide (CZ), Calcipex II® (CII), Vitapex® (V). After seven days, filling paste groups were distributed to 4 subgroups according to cleaning agents (n=5): Control-no cleaning (C), Ethanol (E), Tergenform® (T), 35% Phosphoric acid (PA). Then, the roots were sectioned and the dentin root sections were internally evaluated by FT-Raman, µ-EDXRF and SEM. Data was submitted to two-way ANOVA and Tukey tests (α=0.05). Results Regarding filling pastes, there was no significant difference in organic content. CP provided the lowest calcium values and, calcium/phosphoric ratio (Ca/P), and the highest phosphoric values. For cleaning agents there was no difference in organic content when compared to the C; however, T showed significantly higher calcium and Ca/P than PA. All groups showed similar results for phosphorus. The dentin smear layer was present after use of the cleaning agents, except PA. Conclusion The filling pastes changed the inorganic content, however they did not change the organic content. Cleaning agents did not alter the inorganic and organic content. PA cleaned and opened dentin tubules. PMID:28198982

ANTIMICROBIAL ACTIVITY OF SODIUM HYPOCHLORITE ASSOCIATED WITH INTRACANAL MEDICATION FOR Candida albicans AND Enterococcus faecalis INOCULATED IN ROOT CANALS

PubMed Central

Valera, Marcia Carneiro; da Silva, Katy Costa Godinho; Maekawa, Lilian Eiko; Carvalho, Cláudio Antonio Talge; Koga-Ito, Cristiane Yumi; Camargo, Carlos Henrique Ribeiro; Silva e Lima, Raphael

2009-01-01

Objective: The purpose of this study was to evaluate the action of sodium hypochlorite (NaOCl) associated with an intracanal medication against Candida albicans and Enterococcus faecalis inoculated in root canals. Material and Methods: Thirty-six human single-rooted teeth with single root canals were used. The canals were contaminated with C. albicans and E. faecalis for 21 days and were then instrumented with 1% NaOCl. The roots were divided into 3 groups (n=12) according to the intracanal medication applied: calcium hydroxide paste, 2% chlorhexidine (CHX) gel, and 2% CHX gel associated with calcium hydroxide. The following collections were made from the root canals: a) initial sample (IS): 21 days after contamination (control), b) S1: after instrumentation, c) S2: 14 days after intracanal medication placement; S3: 7 days after intracanal medication removal. The results were analyzed statistically by the Kruskal-Wallis test at 5% significance level. Results and Conclusions: Both 1% NaOCl irrigation and the intracanal medications were effective in eliminating E. faecalis and C. albicans inoculated in root canals. PMID:20027425

Antimicrobial activity of sodium hypochlorite associated with intracanal medication for Candida albicans and Enterococcus faecalis inoculated in root canals.

PubMed

Valera, Marcia Carneiro; Silva, Katy Costa Godinho da; Maekawa, Lilian Eiko; Carvalho, Cláudio Antonio Talge; Koga-Ito, Cristiane Yumi; Camargo, Carlos Henrique Ribeiro; Lima, Raphael Silva e

2009-01-01

The purpose of this study was to evaluate the action of sodium hypochlorite (NaOCl) associated with an intracanal medication against Candida albicans and Enterococcus faecalis inoculated in root canals. Thirty-six human single-rooted teeth with single root canals were used. The canals were contaminated with C. albicans and E. faecalis for 21 days and were then instrumented with 1% NaOCl. The roots were divided into 3 groups (n=12) according to the intracanal medication applied: calcium hydroxide paste, 2% chlorhexidine (CHX) gel, and 2% CHX gel associated with calcium hydroxide. The following collections were made from the root canals: a) initial sample (IS): 21 days after contamination (control), b) S1: after instrumentation, c) S2: 14 days after intracanal medication placement; S3: 7 days after intracanal medication removal. The results were analyzed statistically by the Kruskal-Wallis test at 5% significance level. Both 1% NaOCl irrigation and the intracanal medications were effective in eliminating E. faecalis and C. albicans inoculated in root canals.

Long term mechanical properties of alkali activated slag

NASA Astrophysics Data System (ADS)

Zhu, J.; Zheng, W. Z.; Xu, Z. Z.; Leng, Y. F.; Qin, C. Z.

2018-01-01

This article reports a study on the microstructural and long-term mechanical properties of the alkali activated slag up to 180 days, and cement paste is studied as the comparison. The mechanical properties including compressive strength, flexural strength, axis tensile strength and splitting tensile strength are analyzed. The results showed that the alkali activated slag had higher compressive and tensile strength, Slag is activated by potassium silicate (K2SiO3) and sodium hydroxide (NaOH) solutions for attaining silicate modulus of 1 using 12 potassium silicate and 5.35% sodium hydroxide. The volume dosage of water is 35% and 42%. The results indicate that alkali activated slag is a kind of rapid hardening and early strength cementitious material with excellent long-term mechanical properties. Single row of holes block compressive strength, single-hole block compressive strength and standard solid brick compressive strength basically meet engineering requirements. The microstructures of alkali activated slag are studied by X-ray diffraction (XRD). The hydration products of alkali-activated slag are assured as hydrated calcium silicate and hydrated calcium aluminate.

Calcium Orthophosphates as Bioceramics: State of the Art

PubMed Central

Dorozhkin, Sergey V.

2010-01-01

In the late 1960s, much interest was raised in regard to biomedical applications of various ceramic materials. A little bit later, such materials were named bioceramics. This review is limited to bioceramics prepared from calcium orthophosphates only, which belong to the categories of bioactive and bioresorbable compounds. There have been a number of important advances in this field during the past 30–40 years. Namely, by structural and compositional control, it became possible to choose whether calcium orthophosphate bioceramics were biologically stable once incorporated within the skeletal structure or whether they were resorbed over time. At the turn of the millennium, a new concept of calcium orthophosphate bioceramics—which is able to promote regeneration of bones—was developed. Presently, calcium orthophosphate bioceramics are available in the form of particulates, blocks, cements, coatings, customized designs for specific applications and as injectable composites in a polymer carrier. Current biomedical applications include artificial replacements for hips, knees, teeth, tendons and ligaments, as well as repair for periodontal disease, maxillofacial reconstruction, augmentation and stabilization of the jawbone, spinal fusion and bone fillers after tumor surgery. Exploratory studies demonstrate potential applications of calcium orthophosphate bioceramics as scaffolds, drug delivery systems, as well as carriers of growth factors, bioactive peptides and/or various types of cells for tissue engineering purposes. PMID:24955932

Layered double hydroxide stability. 2. Formation of Cr(III)-containing layered double hydroxides directly from solution

NASA Technical Reports Server (NTRS)

Boclair, J. W.; Braterman, P. S.; Jiang, J.; Lou, S.; Yarberry, F.

1999-01-01

Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydroxide. Analysis of the resultant titration curves yields solubility constants for these compounds. These are in the order Zn < Ni approximately Co, with a clear preference for formation of the phase with z = 1/3. With Mg2+ as chloride, titration gives a mixture of Cr(OH)3 and Mg(OH)2, but the metal sulfates give Mg2Cr(OH)6 1/2(SO4) by a two-step process. Titrimetric and spectroscopic evidence suggests short-range cation order in the one-step LDH systems.

[Effect of revascularization treatment of immature permanent teeth with endodontic infection].

PubMed

Huang, Yibin; Chen, Ke; Zhang, Ying; Xiong, Huacui; Liu, Caiqi

2013-05-01

To observe the effect of revascularization for treatment of immature teeth with endodontic infection mediated by calcium hydroxide. Seventeen pediatric patients with endodontic infections of the permanent teeth were treated with routine root canal and pulp cavity irrigation and disinfection followed by application of calcium hydroxide paste to the root canal orifice to induce revascularization. Another 17 patients received conventional apexification procedures to serve as the control group. The patients were followed up to observe the therapeutic effect of the treatments. In the revascularization treatment group, 4 cases showed healed periapical lesions 6 to 18 months after the surgery with thickened root canal walls and closure of the apical foramen; in 10 cases, the periapical lesions healed 12 to 18 months postoperatively with lengthened root, thickened root canal wall, and narrowed apical foramen. One patient reported pain and swelling at 2 months, and 2 patients showed the formation of gum fistula and ceased development of the roots at 7 and 8 months. In the control group, the periapical lesions healed in 1 cases at 12 months postoperatively with apical foramen closure; in 11 cases, hard tissues formed in the root apex without obviously lengthened roots 6 to 8 months after the surgery; in 5 cases, no apical barrier formed even 12 to 18 months after the surgery. The overall effective rates were similar between the two groups (P>0.05). Revascularization by calcium hydroxide sealing can promote root development of immature permanent teeth with pulpitis or periradicular periodontitis.

21 CFR 73.2326 - Chromium hydroxide green.

Code of Federal Regulations, 2013 CFR

2013-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

21 CFR 73.2326 - Chromium hydroxide green.

Code of Federal Regulations, 2014 CFR

2014-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

21 CFR 73.2326 - Chromium hydroxide green.

Code of Federal Regulations, 2012 CFR

2012-04-01

... COLOR ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2326 Chromium hydroxide green. (a) Identity and... in coloring externally applied cosmetics, including those intended for use in the area of the eye, in...

Calcium

MedlinePlus

... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

Physicochemical properties of nixtamalized corn flours with and without germ.

PubMed

Vega Rojas, Lineth J; Rojas Molina, Isela; Gutiérrez Cortez, Elsa; Rincón Londoño, Natalia; Acosta Osorio, Andrés A; Del Real López, Alicia; Rodríguez García, Mario E

2017-04-01

This research studied the influence of the germ components on the physicochemical properties of cooked corn and nixtamalized corn flours as a function of the calcium hydroxide content (from 0 to 2.1 w/w) and steeping time (between 0 and 9h). A linear relationship was found between calcium content in germ and steeping time used during nixtamalization process. X-ray diffraction analysis showed that calcium carbonate is formed into the germ structure to 2.1 w/w of calcium hydroxide and 9h steeping time. The presence of the germ improves the development of peak viscosity in flours, and it is related to the increases in calcium concentration in germ and the formation of amylose-lipid complexes. No significant changes were observed in palmitic, stearic, oleic and linoleic acids of corn oil. The levels of further corn oil deterioration were 2.1 w/w of calcium hydroxide concentration and 9h of steeping time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transformation of zinc hydroxide chloride monohydrate to crystalline zinc oxide.

PubMed

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2016-04-25

Thermal decomposition of layered zinc hydroxide double salts provides an interesting alternative synthesis for particles of zinc oxide. Here, we examine the sequence of changes occurring as zinc hydroxide chloride monohydrate (Zn5(OH)8Cl2·H2O) is converted to crystalline ZnO by thermal decomposition. The specific surface area of the resultant ZnO measured by BET was 1.3 m(2) g(-1). A complicating and important factor in this process is that the thermal decomposition of zinc hydroxide chloride is also accompanied by the formation of volatile zinc-containing species under certain conditions. We show that this volatile compound is anhydrous ZnCl2 and its formation is moisture dependent. Therefore, control of atmospheric moisture is an important consideration that affects the overall efficiency of ZnO production by this process.

Bonding by Hydroxide-Catalyzed Hydration and Dehydration

NASA Technical Reports Server (NTRS)

Gwo, Dz-Hung

2008-01-01

A simple, inexpensive method for bonding solid objects exploits hydroxide-catalyzed hydration and dehydration to form silicate-like networks in thin surface and interfacial layers between the objects. The method can be practiced at room temperature or over a wide range of temperatures. The method was developed especially to enable the formation of precise, reliable bonds between precise optical components. The bonds thus formed exhibit the precision and transparency of bonds formed by the conventional optical-contact method and the strength and reliability of high-temperature frit bonds. The method also lends itself to numerous non-optical applications in which there are requirements for precise bonds and/or requirements for bonds, whether precise or imprecise, that can reliably withstand severe environmental conditions. Categories of such non-optical applications include forming composite materials, coating substrates, forming laminate structures, and preparing objects of defined geometry and composition. The method is applicable to materials that either (1) can form silicate-like networks in the sense that they have silicate-like molecular structures that are extensible into silicate-like networks or (2) can be chemically linked to silicate-like networks by means of hydroxide-catalyzed hydration and dehydration. When hydrated, a material of either type features surface hydroxyl (-OH) groups. In this method, a silicate-like network that bonds two substrates can be formed either by a bonding material alone or by the bonding material together with material from either or both of the substrates. Typically, an aqueous hydroxide bonding solution is dispensed and allowed to flow between the mating surfaces by capillary action. If the surface figures of the substrates do not match precisely, bonding could be improved by including a filling material in the bonding solution. Preferably, the filling material should include at least one ingredient that can be hydrated to

Early Age Carbonation Heat and Products of Tricalcium Silicate Paste Subject to Carbon Dioxide Curing

PubMed Central

Li, Zhen; He, Zhen; Shao, Yixin

2018-01-01

This paper presents a study on the carbonation reaction heat and products of tricalcium silicate (C3S) paste exposed to carbon dioxide (CO2) for rapid curing. Reaction heat was measured using a retrofitted micro-calorimeter. The highest heat flow of a C3S paste subject to carbonation curing was 200 times higher than that by hydration, and the cumulative heat released by carbonation was three times higher. The compressive strength of a C3S paste carbonated for 2 h and 24 h was 27.5 MPa and 62.9 MPa, respectively. The 24-h carbonation strength had exceeded the hydration strength at 28 days. The CO2 uptake of a C3S paste carbonated for 2 h and 24 h was 17% and 26%, respectively. The X-ray diffraction (XRD), transmission electron microscope coupled with energy dispersive spectrometer (TEM-EDS), and 29Si magic angle spinning–nuclear magnetic resonance (29Si MAS-NMR) results showed that the products of a carbonated C3S paste were amorphous silica (SiO2) and calcite crystal. There was no trace of calcium silicate hydrate (C–S–H) or other polymorphs of calcium carbonate (CaCO3) detected. PMID:29734681

Binder enhanced refuse derived fuel

DOEpatents

Daugherty, Kenneth E.; Venables, Barney J.; Ohlsson, Oscar O.

1996-01-01

A refuse derived fuel (RDF) pellet having about 11% or more particulate calcium hydroxide which is utilized in a combustionable mixture. The pellets are used in a particulate fuel bring a mixture of 10% or more, on a heat equivalent basis, of the RDF pellet which contains calcium hydroxide as a binder, with 50% or more, on a heat equivalent basis, of a sulphur containing coal. Combustion of the mixture is effective to produce an effluent gas from the combustion zone having a reduced SO.sub.2 and polycyclic aromatic hydrocarbon content of effluent gas from similar combustion materials not containing the calcium hydroxide.

The hypocholesterolemic effect of an antacid containing aluminum hydroxide.

PubMed

Sperber, A D; Henkin, Y; Zuili, I; Bearman, J E; Shany, S

1991-12-01

To evaluate the efficacy, safety, and hypocholesterolemic effect of an aluminum hydroxide-containing antacid in hypercholesterolemic individuals. A prospective, randomized, double-masked, placebo-controlled phase of 2 months' duration, followed by an open-design treatment phase of 2 months' duration and a washout phase of 2 months' duration. Family practice clinics of two rural communities (kibbutzim) in Israel. Fifty-six men and women with hypercholesterolemia (type IIa or IIb). Fifty individuals completed the study. After 2 months of dietary modification (low-fat, low-cholesterol diet), the participants were randomized into two matched groups. Group 1 (28 participants) was treated for 2 months with a chewable antacid tablet containing simethicone, magnesium hydroxide, and 113 mg of aluminum hydroxide per tablet, at a dose of two tablets four times daily. Group 2 (22 participants) was given a similar number of placebo tablets for 2 months. During the following 2 months, both groups received the antacid at the above dose. Lipoprotein levels were evaluated at baseline and every 2 months thereafter for 6 months. Compared with pretreatment levels, Group 1 experienced a decrease in low-density lipoprotein cholesterol (LDL-C) of 9.8% after 2 months (p less than 0.001) and 18.5% after 4 months (p less than 0.001). Compared with Group 2, the decrease in LDL-C in Group 1 was 6.2% at the end of the 2-month double-masked, placebo phase. Although the high-density lipoprotein cholesterol (HDL-C) was also reduced in Group 1 at the end of 4 months of therapy (10.2%), the HDL-C/LDL-C ratio increased by 13% during the same interval (p less than 0.05). The treatment was well tolerated, with minimal side effects. An aluminum hydroxide-containing antacid reduces LDL-C in hypercholesterolemic individuals. Although HDL-C was also reduced to a lesser extent, the overall atherogenic index was improved. Further studies should be conducted to evaluate the long-term safety and efficacy of

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

40 CFR 415.60 - Applicability; description of the chlorine and sodium or potassium hydroxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... chlorine and sodium or potassium hydroxide production subcategory. 415.60 Section 415.60 Protection of... MANUFACTURING POINT SOURCE CATEGORY Chlor-alkali Subcategory (Chlorine and Sodium or Potassium Hydroxide Production) § 415.60 Applicability; description of the chlorine and sodium or potassium hydroxide production...

Improvement of the process for electrochemical impregnation of nickel hydroxide electrodes

NASA Technical Reports Server (NTRS)

Comtat, M.; Lafage, B.; Leonardi, J.

1986-01-01

Nickel hydroxide electrodes containing 11g/dsqm hydroxide, with capacities of 3.6 to 3.8 Ah/dsqm were prepared at 353 K by electrochemical impregnation. The reproducibility of the results is obtained by readjusting the pH before each preparation. The control of each electrode is done during two cycles of charge and discharge following the manufacture by a potential relaxation method.

Vitality preservation of an anomalous maxillary central incisor after endodontic therapy.

PubMed

Kaufman, A Y; Kaffe, I; Littner, M M

1984-06-01

Endodontic treatment of a case of fused immature central incisor with a supernumerary tooth with dens in dente is described. Although a chronic dentoalveolar abscess was diagnosed, vitality test signs were positive. Treatment consisted of pulpotomy with calcium hydroxide paste; after 2 1/2 months a permanent root canal filling was placed in the amputated part. Follow-up 2 years postoperatively indicated that the tooth has maintained its vitality. The periapical area is completely healed, and apical closure is evident.

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent.

PubMed

Georgakopoulos, Evangelos; Santos, Rafael M; Chiang, Yi Wai; Manovic, Vasilije

2017-02-21

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (<2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6∙H2O). Based on its ability to adsorb Ni 2+ , as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications.

Two-way Valorization of Blast Furnace Slag: Synthesis of Precipitated Calcium Carbonate and Zeolitic Heavy Metal Adsorbent

PubMed Central

Georgakopoulos, Evangelos; Santos, Rafael M.; Chiang, Yi Wai; Manovic, Vasilije

2017-01-01

The aim of this work is to present a zero-waste process for storing CO2 in a stable and benign mineral form while producing zeolitic minerals with sufficient heavy metal adsorption capacity. To this end, blast furnace slag, a residue from iron-making, is utilized as the starting material. Calcium is selectively extracted from the slag by leaching with acetic acid (2 M CH3COOH) as the extraction agent. The filtered leachate is subsequently physico-chemically purified and then carbonated to form precipitated calcium carbonate (PCC) of high purity (<2 wt% non-calcium impurities, according to ICP-MS analysis). Sodium hydroxide is added to neutralize the regenerated acetate. The morphological properties of the resulting calcitic PCC are tuned for its potential application as a filler in papermaking. In parallel, the residual solids from the extraction stage are subjected to hydrothermal conversion in a caustic solution (2 M NaOH) that leads to the predominant formation of a particular zeolitic mineral phase (detected by XRD), namely analcime (NaAlSi2O6∙H2O). Based on its ability to adsorb Ni2+, as reported from batch adsorption experiments and ICP-OES analysis, this product can potentially be used in wastewater treatment or for environmental remediation applications. PMID:28287605

21 CFR 172.330 - Calcium pantothenate, calcium chloride double salt.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt... FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.330 Calcium pantothenate, calcium chloride double salt. The food additive calcium chloride double salt of calcium pantothenate may...

Solvent and process for recovery of hydroxide from aqueous mixtures

DOEpatents

Moyer, Bruce A.; Chambliss, C. Kevin; Bonnesen, Peter V.; Keever, Tamara J.

2001-01-01

Hydroxide values and associated alkali metal may be recovered from alkaline aqueous solutions using classes of fluorinated alcohols in a water immiscible solvent. The alcohols are characterized by fluorine substituents which are proximal to the acidic alcohol protons and are located to adjust the acidity of the extractant and the solubility of the extractant in the solvent. A method for stripping the extractant and solvent to regenerate the extractant and purified aqueous hydroxide solution is described.

Nickel hydroxides and related materials: a review of their structures, synthesis and properties

PubMed Central

Hall, David S.; Lockwood, David J.; Bock, Christina; MacDougall, Barry R.

2015-01-01

This review article summarizes the last few decades of research on nickel hydroxide, an important material in physics and chemistry, that has many applications in engineering including, significantly, batteries. First, the structures of the two known polymorphs, denoted as α-Ni(OH)2 and β-Ni(OH)2, are described. The various types of disorder, which are frequently present in nickel hydroxide materials, are discussed including hydration, stacking fault disorder, mechanical stresses and the incorporation of ionic impurities. Several related materials are discussed, including intercalated α-derivatives and basic nickel salts. Next, a number of methods to prepare, or synthesize, nickel hydroxides are summarized, including chemical precipitation, electrochemical precipitation, sol–gel synthesis, chemical ageing, hydrothermal and solvothermal synthesis, electrochemical oxidation, microwave-assisted synthesis, and sonochemical methods. Finally, the known physical properties of the nickel hydroxides are reviewed, including their magnetic, vibrational, optical, electrical and mechanical properties. The last section in this paper is intended to serve as a summary of both the potentially useful properties of these materials and the methods for the identification and characterization of ‘unknown’ nickel hydroxide-based samples. PMID:25663812

Efficacy of desensitizing products containing 8% arginine and calcium carbonate for hypersensitivity relief in MIH-affected molars: an 8-week clinical study.

PubMed

Bekes, Katrin; Heinzelmann, Karolin; Lettner, Stefan; Schaller, Hans-Günter

2017-09-01

The objective of this study was to compare the efficacy in reducing hypersensitivity in molar incisor hypomineralization (MIH)-affected molars immediately and over 8 weeks combining a single in-office application and a homed-based program with desensitizing products containing 8% arginine and calcium carbonate. Nineteen children with at least one MIH-affected molar with hypersensitivity were included. Hypersensitivity was assessed with an evaporative (air) stimulus and a tactile stimulus. Each child received a single in-office treatment with a desensitizing paste containing 8% arginine and calcium carbonate (elmex Sensitive Professional desensitizing paste), followed by 8 weeks of brushing twice daily with a desensitizing toothpaste containing 8% arginine, calcium carbonate with 1450 ppm fluoride (elmex Sensitive Professional toothpaste), using the elmex Sensitive Professional toothbrush. Additionally, the corresponding mouthwash (elmex Sensitive Professional mouthwash) was used. Clinical assessments were made at baseline, immediately after the in-office treatment and after 1, 2, 4 and 8 weeks of brushing twice daily. Fifty-six molars with an air blast hypersensitivity score of 2 or 3 (Schiff Cold Air Sensitivity Scale) were included. Application of the desensitizing paste decreased hypersensitivity significantly immediately and throughout the 8 weeks recalls (p < 0.001). In conclusion, 8% arginine and calcium carbonate were able to reduce hypersensitivity successfully during this 8-week trial. Hypersensitivity is a major complaint in patients with MIH. This is the first study evaluating the desensitizing effect of a desensitizing paste containing 8% arginine and calcium carbonate in patients with MIH.

Targeting Chronic and Neuropathic Pain: The N-type Calcium Channel Comes of Age

PubMed Central

Snutch, Terrance P.

2005-01-01

Summary: The rapid entry of calcium into cells through activation of voltage-gated calcium channels directly affects membrane potential and contributes to electrical excitability, repetitive firing patterns, excitation-contraction coupling, and gene expression. At presynaptic nerve terminals, calcium entry is the initial trigger mediating the release of neurotransmitters via the calcium-dependent fusion of synaptic vesicles and involves interactions with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex of synaptic release proteins. Physiological factors or drugs that affect either presynaptic calcium channel activity or the efficacy of calcium-dependent vesicle fusion have dramatic consequences on synaptic transmission, including that mediating pain signaling. The N-type calcium channel exhibits a number of characteristics that make it an attractive target for therapeutic intervention concerning chronic and neuropathic pain conditions. Within the past year, both U.S. and European regulatory agencies have approved the use of the cationic peptide Prialt for the treatment of intractable pain. Prialt is the first N-type calcium channel blocker approved for clinical use and represents the first new proven mechanism of action for chronic pain intervention in many years. The present review discusses the rationale behind targeting the N-type calcium channel, some of the limitations confronting the widespread clinical application of Prialt, and outlines possible strategies to improve upon Prialt's relatively narrow therapeutic window. PMID:16489373

Nickel hydroxide positive electrode for alkaline rechargeable battery

DOEpatents

Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

2018-04-03

Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

Nickel hydroxide positive electrode for alkaline rechargeable battery

DOEpatents

Young, Kwo; Wang, Lixin; Mays, William; Reichman, Benjamin; Chao-Ian, Hu; Wong, Diana; Nei, Jean

2018-02-20

Certain nickel hydroxide active cathode materials for use in alkaline rechargeable batteries are capable of transferring >1.3 electrons per Ni atom under reversible electrochemical conditions. The specific capacity of the nickel hydroxide active materials is for example .gtoreq.325 mAh/g. The cathode active materials exhibit an additional discharge plateau near 0.8 V vs. a metal hydride (MH) anode. Ni in an oxidation state of less than 2, such as Ni.sup.1+, is able to participate in electrochemical reactions when using the present cathode active materials. It is possible that up to 2.3 electrons, up to 2.5 electrons or more may be transferred per Ni atom under electrochemical conditions.

SCM Paste Samples Exposed To Aggressive Solutions. Cementitious Barriers Partnership

DOE Office of Scientific and Technical Information (OSTI.GOV)

Foster, T.

This report summarizes experimental work performed by SIMCO Technologies Inc. (SIMCO) as part of the Cementitious Barriers Partnership (CBP) project. The test series followed an experimental program dedicated to the study of ordinary Portland cement (OPC) hydrated cement pastes exposed to aggressive solutions. In the present study, the scope is extended to hydrated cement pastes incorporating supplementary cementitious materials (SCM) such as fly ash and ground granulated blast furnace slag (GGBFS). Also, the range of aggressive contact solutions was expanded. The experimental program aimed at testing aggressive contact solutions that more closely mimic the chemical composition of saltstone pore solution.more » Five different solutions, some of which incorporated high levels of carbonate and nitrate, were placed in contact with four different hydrated cement paste mixes. In all solutions, 150 mmol/L of SO 4 2– (14 400 ppm) were present. The solutions included different pH conditions and different sodium content. Two paste mixes were equivalent to Vault 1/4 and Vault 2 concrete mixes used at SRS in storage structures. Two additional paste mixes, cast at the same water-to-cement ratio and using the same cements but without SCMs, were also tested. The damage evolution in samples was monitored using ultrasonic pulse velocity (UPV) and mass measurements. After three and twelve months of exposure conditions, samples were taken out of solution containers and analyzed to perform migration tests and porosity measurements. Globally, results were in line with the previous study and confirmed that high pH may limit the formation of some deleterious phases like gypsum. In this case, ettringite may form but is not necessarily associated with damage. However, the high concentration of sodium may be associated with the formation of an AFm-like mineral called U-phase. The most significant evidences of damage were all associated with the Vault 2 paste analog. This material

Methotrexate intercalated ZnAl-layered double hydroxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakraborty, Manjusha; Dasgupta, Sudip; Soundrapandian, Chidambaram

2011-09-15

The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 A in pristine LDH to 21.3 A in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug moleculemore » in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion. - Graphical abstract: ZnAl-layered double hydroxide intercalated with methotrexate ({approx}34% loading) promises the possibility of use of ZnAl-LDH material as drug carrier and in controlled delivery. Highlights: > ZnAl-layered double hydroxide methotrexate nanohybrid has been synthesized. > XRD and TEM studies on nanohybrid revealed successful intercalation of methotrexate. > TG and CHN analyses showed {approx}34 wt% of methotrexate loading into the nanohybrid. > Possibility of use of ZnAl-LDH material as drug carrier and in delivery.« less

Ionic substitution of Mg2+ for Al3+ and Fe3+ with octahedral coordination in hydroxides facilitate precipitation of layered double hydroxides

NASA Astrophysics Data System (ADS)

Paikaray, Susanta; Essilfie-Dughan, Joseph; Hendry, M. Jim

2018-01-01

Precipitation of hydrotalcite-like layered double hydroxides (HT-LDHs) from CO32--SO42--rich acidic and alkaline aqueous media through ionic substitution of Mg2+ for Al3+ + Fe3+ and vice versa was investigated under ambient conditions. Diffractogram, spectroscopic, microprobe, microscopic, and synchrotron techniques were used to examine the mechanisms involved. The cations facilitated rapid precipitation of HT-LDH in alkaline conditions (pH ≥ 8.2) with SO42- and CO32- as the counter charge balancing interlayer anions, while initial formation of Fe3+- and Al3+-hydroxides in acidic conditions (pH ≥ 2.4) with subsequent transformation to MgAlFe-type HT-LDH (pH ≥ 8.2) occurred through substitution of Mg2+ for Al3+ and Fe3+. Substitution of Al3+ and Fe3+ in Mg2+-hydroxides did not yield HT-LDH, while the reverse, i.e., Mg2+ substitution in Al3+ and Fe3+-hydroxides, produced initial poorly ordered amorphous HT-LDH that gained better crystallinity and crystallite size upon neutralization. Linear combination fit analyses of XANES data suggest schwertmannite constituted the predominant Fe-phase until pH ∼3.7 followed by ferrihydrite and eventually HT-LDH after pH ≥ 10; basaluminite and epsomite constituted the predominant Al and Mg phases until pH ∼4.5, after which HT-LDH with minor Al(OH)3 and HT-LDH with brucite, respectively, predominated. The study highlights that Mg2+ substitution in Al- and Fe-precipitates is the governing mechanism for HT-LDH precipitation in oxic environments through neutralization of acidic cationic aqueous residues.

BIOGEOCHEMICAL PROCESSES CONTROLLING ARSENIC SPECIATION AND BIOTRANSFORMATION IN GRANULAR FERRIC HYDROXIDE COATED SAND

EPA Science Inventory

Arsenic mobilization from solid phase Fe (III) hydroxides is an issue of concern, as water-borne arsenic can migrate into pristine environments, endangering aquatic and human life. In general, metal oxide (hydroxides) exerts a dominating effect on the fate and transport of arseni...

Coextrusion-Based 3D Plotting of Ceramic Pastes for Porous Calcium Phosphate Scaffolds Comprised of Hollow Filaments.

PubMed

Jo, In-Hwan; Koh, Young-Hag; Kim, Hyoun-Ee

2018-05-29

This paper demonstrates the utility of coextrusion-based 3D plotting of ceramic pastes (CoEx-3DP) as a new type of additive manufacturing (AM) technique, which can produce porous calcium phosphate (CaP) ceramic scaffolds comprised of hollow CaP filaments. In this technique, green filaments with a controlled core/shell structure can be produced by coextruding an initial feedrod, comprised of the carbon black (CB) core and CaP shell, through a fine nozzle in an acetone bath and then deposited in a controlled manner according to predetermined paths. In addition, channels in CaP filaments can be created through the removal of the CB cores during heat-treatment. Produced CaP scaffolds had two different types of pores with well-defined geometries: three-dimensionally interconnected pores (~360 × 230 μm² in sizes) and channels (>100 μm in diameter) in hollow CaP filaments. The porous scaffolds showed high compressive strengths of ~12.3 ± 2.2 MPa at a high porosity of ~73 vol % when compressed parallel to the direction of the hollow CaP filaments. In addition, the mechanical properties of porous CaP scaffolds could be tailored by adjusting their porosity, for example, compressive strengths of 4.8 ± 1.1 MPa at a porosity of ~82 vol %. The porous CaP scaffold showed good biocompatibility, which was assessed by in vitro cell tests, where several the cells adhered to and spread actively with the outer and inner surfaces of the hollow CaP filaments.

Color stable phosphors for LED lamps and methods for preparing them

DOEpatents

Murphy, James Edward; Setlur, Anant Achyut; Camardello, Samuel Joseph

2013-11-26

An LED lamp includes a light source configured to emit radiation with a peak intensity at a wavelength between about 250 nm and about 550 nm; and a phosphor composition configured to be radiationally coupled to the light source. The phosphor composition includes particles of a phosphor of formula I, said particles having a coating composition disposed on surfaces thereof; ((Sr.sub.1-zM.sub.z).sub.1-(x+w)A.sub.wCe.sub.x).sub.3(Al.sub.1-ySi.sub.y-)O.sub.4+y+3(x-w)F.sub.1-y-3(x-w) I wherein the coating composition comprises a material selected from aluminum oxide, magnesium oxide, calcium oxide, barium oxide, strontium oxide, zinc oxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, strontium hydroxide, zinc hydroxide, aluminum phosphate, magnesium phosphate, calcium phosphate, barium phosphate, strontium phosphate, and combinations thereof; and A is Li, NA, K, or Rb, or a combination thereof; M is Ca, Ba, Mg, Zn, or a combination thereof; and 0

Magnesium stearine production via direct reaction of palm stearine and magnesium hydroxide

NASA Astrophysics Data System (ADS)

Pratiwi, M.; Ylitervo, P.; Pettersson, A.; Prakoso, T.; Soerawidjaja, T. H.

2017-06-01

The fossil oil production could not compensate with the increase of its consumption, because of this reason the renewable alternative energy source is needed to meet this requirement of this fuel. One of the methods to produce hydrocarbon is by decarboxylation of fatty acids. Vegetable oil and fats are the greatest source of fatty acids, so these can be used as raw material for biohydrocarbon production. From other researchers on their past researchs, by heating base soap from divalent metal, those metal salts will decarboxylate and produce hydrocarbon. This study investigate the process and characterization of magnesium soaps from palm stearine by Blachford method. The metal soaps are synthesized by direct reaction of palm stearine and magnesium hydroxide to produce magnesium stearine and magnesium stearine base soaps at 140-180°C and 6-10 bar for 3-6 hours. The operation process which succeed to gain metal soaps is 180°C, 10 bar, for 3-6 hours. These metal soaps are then compared with commercial magnesium stearate. Based on Thermogravimetry Analysis (TGA) results, the decomposition temperature of all the metal soaps were 250°C. Scanning Electron Microscope with Energy Dispersive X-ray (SEM-EDX) analysis have shown the traces of sodium sulphate for magnesium stearate commercial and magnesium hydroxide for both type of magnesium stearine soaps. The analysis results from Microwave Plasma-Atomic Emission Spectrometry (MP-AES) have shown that the magnesium content of magnesium stearine approximate with magnesium stearate commercial and lower compare with magnesium stearine base soaps. These experiments suggest that the presented saponification process method could produced metal soaps comparable with the commercial metal soaps.

Root End Generation: An Unsung Characteristic Property of MTA-A Case Report

PubMed Central

Dixit, Seema; Dixit, Ashutosh; Kumar, Pravin; Arora, Saurabh

2014-01-01

Management of immature teeth with necrotic pulp and periapical lesion has long presented a challenge. The treatment of choice for such teeth is apexification, which is induction of apical closure to produce more favorable conditions for conventional canal obturation. Traditionally, calcium hydroxide has been used for the apexification of immature permanent teeth, however, Mineral Trioxide Aggregate (MTA) holds significant promise not only as an alternative to multiple treatment visits with calcium hydroxide but also having the potential to induce root end development, eventually forming a completed root apex. This case report presents a successful healing and apexification with the use of calcium hydroxide and MTA. A 5-year follow-up revealed root development with MTA. PMID:24596800

Effect of temperature on hydration kinetics and polymerization of tricalcium silicate in stirred suspensions of CaO-saturated solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grant, Steven A.; Boitnott, Ginger E.; Korhonen, Charles J.

2006-04-15

Tricalcium silicate was hydrated at 274, 278, 283, 298, and 313 K in stirred suspensions of saturated CaO solutions under a nitrogen-gas atmosphere until the end of deceleratory period. The suspension conductivities and energy flows were measured continuously. The individual reaction rates for tricalcium silicate dissolution, calcium silicate hydrate precipitation, and calcium hydroxide precipitation were calculated from these measurements. The results suggest that the proportion of tricalcium silicate dissolved was determined by the rate of tricalcium silicate dissolution and the time to very rapid calcium hydroxide precipitation. The time to very rapid calcium hydroxide precipitation was more sensitive to changesmore » in temperature than was the rate of tricalcium silicate dissolution, so that the proportion of tricalcium silicate hydration dissolved by the deceleratory period increased with decreasing temperature. The average chain length of the calcium silicate hydrate ascertained by magic-angle spinning nuclear magnetic resonance spectroscopy increased with increasing temperature.« less

Structure of bayerite-based lithium-aluminum layered double hydroxides (LDHs): observation of monoclinic symmetry.

PubMed

Britto, Sylvia; Kamath, P Vishnu

2009-12-21

The double hydroxides of Li with Al, obtained by the imbibition of Li salts into bayerite and gibbsite-Al(OH)(3), are not different polytypes of the same symmetry but actually crystallize in two different symmetries. The bayerite-derived double hydroxides crystallize with monoclinic symmetry, while the gibbsite-derived hydroxides crystallize with hexagonal symmetry. Successive metal hydroxide layers in the bayerite-derived LDHs are translated by the vector ( approximately -1/3, 0, 1) with respect to each other. The exigency of hydrogen bonding drives the intercalated Cl(-) ion to a site with 2-fold coordination, whereas the intercalated water occupies a site with 6-fold coordination having a pseudotrigonal prismatic symmetry. The nonideal nature of the interlayer sites has implications for the observed selectivity of Li-Al LDHs toward anions of different symmetries.

Plasma graft-polymerization for synthesis of highly stable hydroxide exchange membrane

NASA Astrophysics Data System (ADS)

Hu, Jue; Zhang, Chengxu; Jiang, Lin; Fang, Shidong; Zhang, Xiaodong; Wang, Xiangke; Meng, Yuedong

2014-02-01

A novel plasma graft-polymerization approach is adopted to prepare hydroxide exchange membranes (HEMs) using cardo polyetherketone powders (PEK-C) and vinylbenzyl chloride. The benzylic chloromethyl groups can be successfully introduced into the PEK-C polymer matrix via plasma graft-polymerization. This approach enables a well preservation in the structure of functional groups and formation of a highly cross-linked structure in the membrane, leading to an improvement on the stability and performance of HEMs. The chemical stabilities, including alkaline and oxidative stability, are evaluated under severe conditions by measuring hydroxide conductivity and weight changes during aging. The obtained PGP-NOH membrane retains 86% of the initial hydroxide conductivity in 6 mol L-1 KOH solution at 60 °C for 120 h, and 94% of the initial weight in 3 wt% H2O2 solution at 60 °C for 262 h. The PGP-NOH membrane also possesses excellent thermal stability (safely used below 120 °C), alcohol resistance (ethanol permeability of 6.6 × 10-11 m2 s-1 and diffusion coefficient of 3.7 × 10-13 m2 s-1), and an acceptable hydroxide conductivity (8.3 mS cm-1 at 20 °C in deionized water), suggesting a good candidate of PGP-NOH membrane for HEMFC applications.

Calcium deprivation increases the palatability of calcium solutions in rats.

PubMed

McCaughey, Stuart A; Forestell, Catherine A; Tordoff, Michael G

2005-02-15

Calcium-deprived rats have elevated intakes of CaCl2, other calcium salts, and some non-calcium compounds. We used taste reactivity to examine the effects of calcium deprivation on the palatability of CaCl2 and other solutions. Nine male Sprague-Dawley rats were calcium-deprived by maintenance on a low-calcium diet, and eight replete rats were used as controls. All rats were videotaped during intraoral infusion of the following solutions: 30 and 300 mM CaCl2, 30 mM calcium lactate, 100 and 600 mM NaCl, 30 mM MgCl2, 1 mM quinine.HCl, 2.5 mM sodium saccharin, and deionized water. We counted individual orofacial and somatic movements elicited by the infusions and used them to calculate total ingestive and aversive scores. Relative to controls, calcium-deprived rats gave a significantly larger number of tongue protrusions and had higher total ingestive scores for CaCl2, calcium lactate, NaCl, and MgCl2. Our results suggest that CaCl2, calcium lactate, NaCl, and MgCl2 taste more palatable to rats when they are calcium-deprived than replete, and this may be responsible for the increased intake of these solutions following calcium deprivation.

Thermochemical Concrete Pavement Scaling Mechanism: Navy F/A-18 Jet Aircraft Parking Apron Problem

DTIC Science & Technology

1998-06-01

boiling and recondensation) in hot, concentrated potassium hydroxide (E): Eqn 11 Alkaline Hydrolysis of Esters with Potassium Hydroxide KOH...RC02R’ -> KC02R + R’OH potassium alkyl ester (B) potassium ethanol(L) hydroxide (E) carboxylate (F) The overall reaction appears to make sense...carbonate (H) water 2. The parallel between calcium hydroxide and potassium hydroxide is not very accurate. Potassium hydroxide is a much stronger alkali

Alkalization of tumor microenvironment for cancer treatment

NASA Astrophysics Data System (ADS)

Lozhkomoev, A. S.

2017-09-01

The paper is devoted to describing how boehmite, magnesium hydroxide and calcium hydroxide nanoparticles in the form of nanoplates with a size of 20-200 nm having cytotoxic properties to tumor cells were synthesized. It is shown that calcium hydroxide has the highest cytotoxicity, while boehmite has the lowest one. The characterization of the synthesized nanostructures demonstrated that the major antitumor factors probably are the acid-base surface properties. It is established that calcium hydroxide raises the pH of the cell culture medium up to 12.8, magnesium hydroxide—up to 10.8, boehmite—up to 8.6. At the same time, synthesized nanoplates are less toxic to the normal cell lines. The approach presented can be used for synthesis of materials that are able to change tumor cells microenvironment acidity in the defined range for anticancer therapy, and also potentiating standard chemotherapy drugs effect due to extracellular acidosis decreasing.

Calcium ionization balance and argon/calcium abundance in solar flares

NASA Astrophysics Data System (ADS)

Antonucci, E.; Marocchi, D.; Gabriel, A. H.; Doschek, G. A.

1987-12-01

An earlier analysis of solar flare calcium spectra from XRP and P78-1 aimed at measuring the calcium ionization balance resulted in an ambiguity due to a line blend between the calcium q line and an Ar XVII line. In the present work the calcium line 'r' is included in the analysis in order to resolve this problem. It is shown that the correct calcium ionization balance is that indicated in the earlier paper as corresponding to an argon/calcium abundance ratio of 0.2. The argon/calcium abundance ratio in the group of solar flares studied is shown to be 0.2 + or - 0.2. It is further argued that while the abundance of heavy elements may be enhanced in energetic flare events, this enhancement is less for argon than for calcium, leading to an argon/calcium ratio smaller than that present in the quiet sun.

Recycling Lithium Carbonate/Lithium Hydroxide Waste

NASA Technical Reports Server (NTRS)

Flowers, J.; Flowers, J.

1983-01-01

Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2011 CFR

2011-04-01

... thickener as defined in § 170.3(o)(28) of this chapter. (2) The ingredient is used in food at levels not to... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Potassium hydroxide. 184.1631 Section 184.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD...

21 CFR 184.1631 - Potassium hydroxide.

Code of Federal Regulations, 2010 CFR

2010-04-01

... thickener as defined in § 170.3(o)(28) of this chapter. (2) The ingredient is used in food at levels not to... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium hydroxide. 184.1631 Section 184.1631 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

Kinetics of de-N-acetylation of the chitin disaccharide in aqueous sodium hydroxide solution.

PubMed

Khong, Thang Trung; Aachmann, Finn L; Vårum, Kjell M

2012-05-01

Chitosan is prepared from chitin, a process which is carried out at highly alkaline conditions, and that can be performed either on chitin in solution (homogeneous deacetylation) or heterogeneously with the chitin as a solid throughout the reaction. We report here a study of the de-N-acetylation reaction of the chitin dimer (GlcNAc-GlcNAc) in solution. The reaction was followed by (1)H NMR spectroscopy in deuterated aqueous sodium hydroxide solution as a function of time, sodium-hydroxide concentration and temperature. The (1)H NMR spectrum of GlcNAc-GlcNAc in 2.77 M deuterated aqueous sodium hydroxide solution was assigned. The interpretation of the (1)H NMR spectra allowed us to determine the rates of de-N-acetylation of the reducing and non-reducing ends, showing that the reaction rate at the reducing end is twice the rate at the non-reducing end. The total deacetylation reaction rate was determined as a function of the hydroxide ion concentration, showing for the first time that this de-N-acetylation reaction is second order with respect to hydroxide ion concentration. No significant difference in the deacetylation rates in deuterated water compared to water was observed. The activation energy for the reaction (26-54 °C) was determined to 114.4 and 98.6 kJ/mol at 2.77 and 5.5 M in deuterated aqueous sodium hydroxide solution, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Automated solid-phase extraction of phenolic acids using layered double hydroxide-alumina-polymer disks.

PubMed

Ghani, Milad; Palomino Cabello, Carlos; Saraji, Mohammad; Manuel Estela, Jose; Cerdà, Víctor; Turnes Palomino, Gemma; Maya, Fernando

2018-01-26

The application of layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks for solid-phase extraction is reported for the first time. Al 2 O 3 is embedded in a polymer matrix followed by an in situ metal-exchange process to obtain a layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disk with excellent flow-through properties. The extraction performance of the prepared disks is evaluated as a proof of concept for the automated extraction using sequential injection analysis of organic acids (p-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid) following an anion-exchange mechanism. After the solid-phase extraction, phenolic acids were quantified by reversed-phase high-performance liquid chromatography with diode-array detection using a core-shell silica-C18 stationary phase and isocratic elution (acetonitrile/0.5% acetic acid in pure water, 5:95, v/v). High sensitivity and reproducibility were obtained with limits of detection in the range of 0.12-0.25 μg/L (sample volume, 4 mL), and relative standard deviations between 2.9 and 3.4% (10 μg/L, n = 6). Enrichment factors of 34-39 were obtained. Layered double hydroxide-Al 2 O 3 -polymer mixed-matrix disks had an average lifetime of 50 extractions. Analyte recoveries ranged from 93 to 96% for grape juice and nonalcoholic beer samples. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Calcium Carbonate

MedlinePlus

... Maalox® (as a combination product containing Calcium Carbonate, Simethicone) ... Relief (as a combination product containing Calcium Carbonate, Simethicone) ... Plus (as a combination product containing Calcium Carbonate, Simethicone)

Risk of calcium oxalate nephrolithiasis in postmenopausal women supplemented with calcium or combined calcium and estrogen.

PubMed

Domrongkitchaiporn, Somnuek; Ongphiphadhanakul, Boonsong; Stitchantrakul, Wasana; Chansirikarn, Sirinthorn; Puavilai, Gobchai; Rajatanavin, Rajata

2002-02-26

Recent studies showed that postmenopausal women lost less bone mass when supplemented with calcium or estrogen therapy. However, the safety of the treatments in terms of the risk of calcium oxalate stone formation is unknown. We therefore conducted this study to determine the alteration in calcium oxalate supersaturation after calcium supplement or after combined calcium and estrogen therapy in postmenopausal osteoporotic women. Fifty-six postmenopausal women were enrolled in this study. All subjects were more than 10 years postmenopausal with vertebral or femoral osteoporosis by bone mineral density criteria. They were randomly allocated to receive either 625 mg of calcium carbonate (250 mg of elemental calcium) at the end of a meal three times a day (group A, n=26) or calcium carbonate in the same manner plus 0.625 mg/day of conjugated equine estrogen and 5 mg medrogestone acetate from day 1-12 each month (group B, n=30). The age (mean +/- S.E.M.) was 66.3 +/- 1.2 and 65.1 +/- 1.1 years, weight 54.1 +/- 1.2 and 55.3 +/- 2.1 kg, in group A and group B, respectively. Urine specimens (24-h) were collected at baseline and 3 months after treatment for the determination of calcium oxalate saturation by using Tiselius's index (AP(CaOx)) and calcium/citrate ratio. After 3 months of treatment, there was no significant alteration from baseline for urinary excretion of calcium, citrate and oxalate. Urinary phosphate excretion was significantly reduced (6.3 +/- 0.7 vs. 5.1 +/- 0.7 mmol/day for group A and 8.2 +/- 0.9 vs. 5.8 +/- 0.7 mmol/day for group B, P<0.05), whereas net alkaline absorption was significantly elevated (10.1 +/- 3.6 vs. 20.1 +/- 4.4 meq/day for group A and 4.8 +/- 3.2 vs. 19.9 +/- 3.6 meq/day for group B, P<0.05). Calcium/citrate ratio and AP(CaOx) determined at baseline were not different from the corresponding values after treatment in both groups; calcium/citrate: 10.1 +/- 3.1 vs. 10.1 +/- 2.5 for group A and 9.3 +/- 1.8 vs. 11.9 +/- 2.5 for group B and

Electrodeposition of Zn-doped α-nickel hydroxide with flower-like nanostructure for supercapacitors

NASA Astrophysics Data System (ADS)

You, Zheng; Shen, Kui; Wu, Zhicheng; Wang, Xiaofeng; Kong, Xianghua

2012-08-01

Zn-doped α-nickel hydroxide materials with flower-like nanostructures are synthesized by electrochemical deposition method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (SEM) and electrochemical measurements. XRD spectra indicate nickel hydroxide doped with Zn is α-Ni(OH)2 with excellent crystallization. The SEM observation shows that the formation of Zn-doped Ni(OH)2 includes two steps: a honeycomb-like film forms on the substrate first, then flower-like particles forms on the films. The nickel hydroxide doped with 5% Zn can maintain a maximum specific capacitance of 860 F g-1, suggesting its potential application in electrochemical capacitors.

Structural Differentiation between Layered Single (Ni) and Double Metal Hydroxides (Ni–Al LDHs) Using Wavelet Transformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siebecker, Matthew G.; Sparks, Donald L.

2017-09-07

Layered double hydroxides (LDHs) are anionic clays important in disciplines such as environmental chemistry, geochemistry, and materials science. Developments in signal processing of extended X-ray absorption fine structure (EXAFS) data, such as wavelet transformation (WT), have been used to identify transition metals and Al present in the hydroxide sheets of LDHs. The WT plots of LDHs should be distinct from those of isostructural single metal hydroxides. However, no direct comparison of these minerals appears in the literature using WT. This work systematically analyzes a suite of Ni-rich mineral standards, including Ni–Al LDHs, single metal Ni hydroxides, and Ni-rich silicates usingmore » WT. The results illustrate that the WT plots for α-Ni(OH)2 and Ni–Al LDHs are often indistinguishable from each other, with similar two-component plots for the different mineral types. This demonstrates that the WT of the first metal shell often cannot be used to differentiate an LDH from a single metal hydroxide. Interlayer anions adsorbed to the hydroxide sheet of α-Ni(OH)2 affect the EXAFS spectra and are not visible in the FT but are clearly resolved and discrete in the WT.« less

CALCIUM CHLORIDE PLANT LOOKING EAST. CALCIUM CHLORIDE BUILDING IN CENTER, ...

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